diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/native/ApiClient.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/native/ApiClient.mustache
index 14add046a0..a641525af1 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/native/ApiClient.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/native/ApiClient.mustache
@@ -57,7 +57,7 @@ public class ApiClient {
   private Duration readTimeout;
   private Duration connectTimeout;
 
-  private static String valueToString(Object value) {
+  public static String valueToString(Object value) {
     if (value == null) {
       return "";
     }
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/native/pojo.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/native/pojo.mustache
index 15bd2f96d2..f5b7d071a2 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/native/pojo.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/native/pojo.mustache
@@ -1,6 +1,9 @@
 {{#discriminator}}
 import {{invokerPackage}}.JSON;
 {{/discriminator}}
+{{#supportUrlQuery}}
+import {{invokerPackage}}.ApiClient;
+{{/supportUrlQuery}}
 /**
  * {{description}}{{^description}}{{classname}}{{/description}}{{#isDeprecated}}
  * @deprecated{{/isDeprecated}}
@@ -408,7 +411,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
       for ({{{items.dataType}}} _item : {{getter}}()) {
         joiner.add(String.format("%s{{baseName}}%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(_item), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(_item), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
       i++;
     }
@@ -418,7 +421,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
       for (int i = 0; i < {{getter}}().size(); i++) {
         joiner.add(String.format("%s{{baseName}}%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf({{getter}}().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString({{getter}}().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
     {{/uniqueItems}}
@@ -456,7 +459,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
         if (_item != null) {
           joiner.add(String.format("%s{{baseName}}%s%s=%s", prefix, suffix,
               "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-              URLEncoder.encode(String.valueOf(_item), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+              URLEncoder.encode(ApiClient.valueToString(_item), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
         }
         i++;
       }
@@ -468,7 +471,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
         if ({{getter}}().get(i) != null) {
           joiner.add(String.format("%s{{baseName}}%s%s=%s", prefix, suffix,
               "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-              URLEncoder.encode(String.valueOf({{getter}}().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+              URLEncoder.encode(ApiClient.valueToString({{getter}}().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
         }
       }
     }
@@ -483,7 +486,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
       for (String _key : {{getter}}().keySet()) {
         joiner.add(String.format("%s{{baseName}}%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            {{getter}}().get(_key), URLEncoder.encode(String.valueOf({{getter}}().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            {{getter}}().get(_key), URLEncoder.encode(ApiClient.valueToString({{getter}}().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
     {{/items.isModel}}
@@ -501,7 +504,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
     {{^isMap}}
     {{#isPrimitiveType}}
     if ({{getter}}() != null) {
-      joiner.add(String.format("%s{{{baseName}}}%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf({{{getter}}}()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%s{{{baseName}}}%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString({{{getter}}}()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
     {{/isPrimitiveType}}
     {{^isPrimitiveType}}
@@ -512,7 +515,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
     {{/isModel}}
     {{^isModel}}
     if ({{getter}}() != null) {
-      joiner.add(String.format("%s{{{baseName}}}%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf({{{getter}}}()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%s{{{baseName}}}%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString({{{getter}}}()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
     {{/isModel}}
     {{/isPrimitiveType}}
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/ApiClient.java
index fd1f548247..4b8dcd83a4 100644
--- a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/ApiClient.java
@@ -66,7 +66,7 @@ public class ApiClient {
   private Duration readTimeout;
   private Duration connectTimeout;
 
-  private static String valueToString(Object value) {
+  public static String valueToString(Object value) {
     if (value == null) {
       return "";
     }
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/Bird.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/Bird.java
index fa6c12e702..f6c0268eff 100644
--- a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/Bird.java
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/Bird.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Bird
  */
@@ -172,12 +173,12 @@ public class Bird {
 
     // add `size` to the URL query string
     if (getSize() != null) {
-      joiner.add(String.format("%ssize%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getSize()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%ssize%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getSize()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `color` to the URL query string
     if (getColor() != null) {
-      joiner.add(String.format("%scolor%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getColor()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%scolor%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getColor()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/Category.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/Category.java
index 6bd14e67da..fde6c29839 100644
--- a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/Category.java
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/Category.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Category
  */
@@ -172,12 +173,12 @@ public class Category {
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/DataQuery.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/DataQuery.java
index 4227a694ac..699122d09e 100644
--- a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/DataQuery.java
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/DataQuery.java
@@ -32,6 +32,7 @@ import org.openapitools.client.model.Query;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * DataQuery
  */
@@ -221,7 +222,7 @@ public class DataQuery extends Query {
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `outcomes` to the URL query string
@@ -229,23 +230,23 @@ public class DataQuery extends Query {
       for (int i = 0; i < getOutcomes().size(); i++) {
         joiner.add(String.format("%soutcomes%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getOutcomes().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getOutcomes().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
     // add `suffix` to the URL query string
     if (getSuffix() != null) {
-      joiner.add(String.format("%ssuffix%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getSuffix()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%ssuffix%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getSuffix()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `text` to the URL query string
     if (getText() != null) {
-      joiner.add(String.format("%stext%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getText()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%stext%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getText()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `date` to the URL query string
     if (getDate() != null) {
-      joiner.add(String.format("%sdate%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getDate()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sdate%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getDate()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/DefaultValue.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/DefaultValue.java
index f6752d0155..087ffb4cdb 100644
--- a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/DefaultValue.java
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/DefaultValue.java
@@ -35,6 +35,7 @@ import java.util.NoSuchElementException;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * to test the default value of properties
  */
@@ -505,7 +506,7 @@ public class DefaultValue {
         if (getArrayStringEnumRefDefault().get(i) != null) {
           joiner.add(String.format("%sarray_string_enum_ref_default%s%s=%s", prefix, suffix,
               "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-              URLEncoder.encode(String.valueOf(getArrayStringEnumRefDefault().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+              URLEncoder.encode(ApiClient.valueToString(getArrayStringEnumRefDefault().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
         }
       }
     }
@@ -515,7 +516,7 @@ public class DefaultValue {
       for (int i = 0; i < getArrayStringEnumDefault().size(); i++) {
         joiner.add(String.format("%sarray_string_enum_default%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getArrayStringEnumDefault().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getArrayStringEnumDefault().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -524,7 +525,7 @@ public class DefaultValue {
       for (int i = 0; i < getArrayStringDefault().size(); i++) {
         joiner.add(String.format("%sarray_string_default%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getArrayStringDefault().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getArrayStringDefault().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -533,7 +534,7 @@ public class DefaultValue {
       for (int i = 0; i < getArrayIntegerDefault().size(); i++) {
         joiner.add(String.format("%sarray_integer_default%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getArrayIntegerDefault().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getArrayIntegerDefault().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -542,7 +543,7 @@ public class DefaultValue {
       for (int i = 0; i < getArrayString().size(); i++) {
         joiner.add(String.format("%sarray_string%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getArrayString().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getArrayString().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -551,7 +552,7 @@ public class DefaultValue {
       for (int i = 0; i < getArrayStringNullable().size(); i++) {
         joiner.add(String.format("%sarray_string_nullable%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getArrayStringNullable().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getArrayStringNullable().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -560,13 +561,13 @@ public class DefaultValue {
       for (int i = 0; i < getArrayStringExtensionNullable().size(); i++) {
         joiner.add(String.format("%sarray_string_extension_nullable%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getArrayStringExtensionNullable().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getArrayStringExtensionNullable().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
     // add `string_nullable` to the URL query string
     if (getStringNullable() != null) {
-      joiner.add(String.format("%sstring_nullable%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getStringNullable()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sstring_nullable%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getStringNullable()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/NumberPropertiesOnly.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/NumberPropertiesOnly.java
index 98a3933675..431081d5e2 100644
--- a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/NumberPropertiesOnly.java
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/NumberPropertiesOnly.java
@@ -29,6 +29,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * NumberPropertiesOnly
  */
@@ -206,17 +207,17 @@ public class NumberPropertiesOnly {
 
     // add `number` to the URL query string
     if (getNumber() != null) {
-      joiner.add(String.format("%snumber%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getNumber()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%snumber%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getNumber()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `float` to the URL query string
     if (getFloat() != null) {
-      joiner.add(String.format("%sfloat%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getFloat()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sfloat%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getFloat()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `double` to the URL query string
     if (getDouble() != null) {
-      joiner.add(String.format("%sdouble%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getDouble()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sdouble%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getDouble()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/Pet.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/Pet.java
index 6620aa54d5..3d59e13e74 100644
--- a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/Pet.java
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/Pet.java
@@ -32,6 +32,7 @@ import org.openapitools.client.model.Tag;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Pet
  */
@@ -353,12 +354,12 @@ public class Pet {
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `category` to the URL query string
@@ -371,7 +372,7 @@ public class Pet {
       for (int i = 0; i < getPhotoUrls().size(); i++) {
         joiner.add(String.format("%sphotoUrls%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getPhotoUrls().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getPhotoUrls().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -387,7 +388,7 @@ public class Pet {
 
     // add `status` to the URL query string
     if (getStatus() != null) {
-      joiner.add(String.format("%sstatus%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getStatus()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sstatus%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getStatus()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/Query.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/Query.java
index 9385588414..3516d42378 100644
--- a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/Query.java
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/Query.java
@@ -30,6 +30,7 @@ import java.util.List;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Query
  */
@@ -219,7 +220,7 @@ public class Query {
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `outcomes` to the URL query string
@@ -227,7 +228,7 @@ public class Query {
       for (int i = 0; i < getOutcomes().size(); i++) {
         joiner.add(String.format("%soutcomes%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getOutcomes().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getOutcomes().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/Tag.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/Tag.java
index 75cf65e394..3b5269ef19 100644
--- a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/Tag.java
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/Tag.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Tag
  */
@@ -172,12 +173,12 @@ public class Tag {
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/TestFormObjectMultipartRequestMarker.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/TestFormObjectMultipartRequestMarker.java
index c5e922a650..2daf35f63c 100644
--- a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/TestFormObjectMultipartRequestMarker.java
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/TestFormObjectMultipartRequestMarker.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * TestFormObjectMultipartRequestMarker
  */
@@ -141,7 +142,7 @@ public class TestFormObjectMultipartRequestMarker {
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter.java
index d8517ba91e..d6a413b441 100644
--- a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter.java
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter
  */
@@ -234,22 +235,22 @@ public class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter
 
     // add `size` to the URL query string
     if (getSize() != null) {
-      joiner.add(String.format("%ssize%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getSize()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%ssize%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getSize()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `color` to the URL query string
     if (getColor() != null) {
-      joiner.add(String.format("%scolor%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getColor()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%scolor%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getColor()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter.java
index 7b8fe822f9..c66f16d3a3 100644
--- a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter.java
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/model/TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter.java
@@ -30,6 +30,7 @@ import java.util.List;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter
  */
@@ -154,7 +155,7 @@ public class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter {
       for (int i = 0; i < getValues().size(); i++) {
         joiner.add(String.format("%svalues%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getValues().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getValues().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/ApiClient.java
index 492e9aea50..6092094f1b 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/ApiClient.java
@@ -66,7 +66,7 @@ public class ApiClient {
   private Duration readTimeout;
   private Duration connectTimeout;
 
-  private static String valueToString(Object value) {
+  public static String valueToString(Object value) {
     if (value == null) {
       return "";
     }
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/AdditionalPropertiesClass.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/AdditionalPropertiesClass.java
index d4d7553e71..3422bfa21e 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/AdditionalPropertiesClass.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/AdditionalPropertiesClass.java
@@ -34,6 +34,7 @@ import java.util.NoSuchElementException;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * AdditionalPropertiesClass
  */
@@ -418,7 +419,7 @@ public class AdditionalPropertiesClass {
       for (String _key : getMapProperty().keySet()) {
         joiner.add(String.format("%smap_property%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getMapProperty().get(_key), URLEncoder.encode(String.valueOf(getMapProperty().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getMapProperty().get(_key), URLEncoder.encode(ApiClient.valueToString(getMapProperty().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -427,23 +428,23 @@ public class AdditionalPropertiesClass {
       for (String _key : getMapOfMapProperty().keySet()) {
         joiner.add(String.format("%smap_of_map_property%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getMapOfMapProperty().get(_key), URLEncoder.encode(String.valueOf(getMapOfMapProperty().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getMapOfMapProperty().get(_key), URLEncoder.encode(ApiClient.valueToString(getMapOfMapProperty().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
     // add `anytype_1` to the URL query string
     if (getAnytype1() != null) {
-      joiner.add(String.format("%sanytype_1%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getAnytype1()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sanytype_1%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getAnytype1()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `map_with_undeclared_properties_anytype_1` to the URL query string
     if (getMapWithUndeclaredPropertiesAnytype1() != null) {
-      joiner.add(String.format("%smap_with_undeclared_properties_anytype_1%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getMapWithUndeclaredPropertiesAnytype1()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%smap_with_undeclared_properties_anytype_1%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getMapWithUndeclaredPropertiesAnytype1()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `map_with_undeclared_properties_anytype_2` to the URL query string
     if (getMapWithUndeclaredPropertiesAnytype2() != null) {
-      joiner.add(String.format("%smap_with_undeclared_properties_anytype_2%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getMapWithUndeclaredPropertiesAnytype2()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%smap_with_undeclared_properties_anytype_2%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getMapWithUndeclaredPropertiesAnytype2()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `map_with_undeclared_properties_anytype_3` to the URL query string
@@ -451,13 +452,13 @@ public class AdditionalPropertiesClass {
       for (String _key : getMapWithUndeclaredPropertiesAnytype3().keySet()) {
         joiner.add(String.format("%smap_with_undeclared_properties_anytype_3%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getMapWithUndeclaredPropertiesAnytype3().get(_key), URLEncoder.encode(String.valueOf(getMapWithUndeclaredPropertiesAnytype3().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getMapWithUndeclaredPropertiesAnytype3().get(_key), URLEncoder.encode(ApiClient.valueToString(getMapWithUndeclaredPropertiesAnytype3().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
     // add `empty_map` to the URL query string
     if (getEmptyMap() != null) {
-      joiner.add(String.format("%sempty_map%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getEmptyMap()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sempty_map%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getEmptyMap()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `map_with_undeclared_properties_string` to the URL query string
@@ -465,7 +466,7 @@ public class AdditionalPropertiesClass {
       for (String _key : getMapWithUndeclaredPropertiesString().keySet()) {
         joiner.add(String.format("%smap_with_undeclared_properties_string%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getMapWithUndeclaredPropertiesString().get(_key), URLEncoder.encode(String.valueOf(getMapWithUndeclaredPropertiesString().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getMapWithUndeclaredPropertiesString().get(_key), URLEncoder.encode(ApiClient.valueToString(getMapWithUndeclaredPropertiesString().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Animal.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Animal.java
index 2ac28c4553..7cc3bb0fd9 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Animal.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Animal.java
@@ -32,6 +32,7 @@ import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
 import org.openapitools.client.JSON;
+import org.openapitools.client.ApiClient;
 /**
  * Animal
  */
@@ -186,12 +187,12 @@ public class Animal {
 
     // add `className` to the URL query string
     if (getClassName() != null) {
-      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `color` to the URL query string
     if (getColor() != null) {
-      joiner.add(String.format("%scolor%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getColor()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%scolor%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getColor()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Apple.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Apple.java
index ad1e70dc43..0b841d2cda 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Apple.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Apple.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Apple
  */
@@ -172,12 +173,12 @@ public class Apple {
 
     // add `cultivar` to the URL query string
     if (getCultivar() != null) {
-      joiner.add(String.format("%scultivar%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getCultivar()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%scultivar%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getCultivar()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `origin` to the URL query string
     if (getOrigin() != null) {
-      joiner.add(String.format("%sorigin%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getOrigin()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sorigin%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getOrigin()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/AppleReq.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/AppleReq.java
index deeb3e13fc..ee00bb8973 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/AppleReq.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/AppleReq.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * AppleReq
  */
@@ -172,12 +173,12 @@ public class AppleReq {
 
     // add `cultivar` to the URL query string
     if (getCultivar() != null) {
-      joiner.add(String.format("%scultivar%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getCultivar()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%scultivar%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getCultivar()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `mealy` to the URL query string
     if (getMealy() != null) {
-      joiner.add(String.format("%smealy%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getMealy()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%smealy%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getMealy()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ArrayOfArrayOfNumberOnly.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ArrayOfArrayOfNumberOnly.java
index 4a9bef3b24..781d654cc3 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ArrayOfArrayOfNumberOnly.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ArrayOfArrayOfNumberOnly.java
@@ -31,6 +31,7 @@ import java.util.List;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * ArrayOfArrayOfNumberOnly
  */
@@ -156,7 +157,7 @@ public class ArrayOfArrayOfNumberOnly {
         if (getArrayArrayNumber().get(i) != null) {
           joiner.add(String.format("%sArrayArrayNumber%s%s=%s", prefix, suffix,
               "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-              URLEncoder.encode(String.valueOf(getArrayArrayNumber().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+              URLEncoder.encode(ApiClient.valueToString(getArrayArrayNumber().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
         }
       }
     }
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ArrayOfNumberOnly.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ArrayOfNumberOnly.java
index 3da690b9c0..5ce6272649 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ArrayOfNumberOnly.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ArrayOfNumberOnly.java
@@ -31,6 +31,7 @@ import java.util.List;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * ArrayOfNumberOnly
  */
@@ -156,7 +157,7 @@ public class ArrayOfNumberOnly {
         if (getArrayNumber().get(i) != null) {
           joiner.add(String.format("%sArrayNumber%s%s=%s", prefix, suffix,
               "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-              URLEncoder.encode(String.valueOf(getArrayNumber().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+              URLEncoder.encode(ApiClient.valueToString(getArrayNumber().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
         }
       }
     }
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ArrayTest.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ArrayTest.java
index 5c58f262ed..3bcb33a5cf 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ArrayTest.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ArrayTest.java
@@ -31,6 +31,7 @@ import org.openapitools.client.model.ReadOnlyFirst;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * ArrayTest
  */
@@ -233,7 +234,7 @@ public class ArrayTest {
       for (int i = 0; i < getArrayOfString().size(); i++) {
         joiner.add(String.format("%sarray_of_string%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getArrayOfString().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getArrayOfString().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -242,7 +243,7 @@ public class ArrayTest {
       for (int i = 0; i < getArrayArrayOfInteger().size(); i++) {
         joiner.add(String.format("%sarray_array_of_integer%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getArrayArrayOfInteger().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getArrayArrayOfInteger().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -252,7 +253,7 @@ public class ArrayTest {
         if (getArrayArrayOfModel().get(i) != null) {
           joiner.add(String.format("%sarray_array_of_model%s%s=%s", prefix, suffix,
               "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-              URLEncoder.encode(String.valueOf(getArrayArrayOfModel().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+              URLEncoder.encode(ApiClient.valueToString(getArrayArrayOfModel().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
         }
       }
     }
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Banana.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Banana.java
index a05fbe2f29..63beebe105 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Banana.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Banana.java
@@ -29,6 +29,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Banana
  */
@@ -142,7 +143,7 @@ public class Banana {
 
     // add `lengthCm` to the URL query string
     if (getLengthCm() != null) {
-      joiner.add(String.format("%slengthCm%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getLengthCm()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%slengthCm%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getLengthCm()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/BananaReq.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/BananaReq.java
index 25314afb3b..e8ee1977b6 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/BananaReq.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/BananaReq.java
@@ -29,6 +29,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * BananaReq
  */
@@ -173,12 +174,12 @@ public class BananaReq {
 
     // add `lengthCm` to the URL query string
     if (getLengthCm() != null) {
-      joiner.add(String.format("%slengthCm%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getLengthCm()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%slengthCm%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getLengthCm()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `sweet` to the URL query string
     if (getSweet() != null) {
-      joiner.add(String.format("%ssweet%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getSweet()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%ssweet%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getSweet()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/BasquePig.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/BasquePig.java
index cd148b4292..60cdf6b778 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/BasquePig.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/BasquePig.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * BasquePig
  */
@@ -141,7 +142,7 @@ public class BasquePig {
 
     // add `className` to the URL query string
     if (getClassName() != null) {
-      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Capitalization.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Capitalization.java
index 221eb6bc1b..5a4a72a374 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Capitalization.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Capitalization.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Capitalization
  */
@@ -296,32 +297,32 @@ public class Capitalization {
 
     // add `smallCamel` to the URL query string
     if (getSmallCamel() != null) {
-      joiner.add(String.format("%ssmallCamel%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getSmallCamel()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%ssmallCamel%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getSmallCamel()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `CapitalCamel` to the URL query string
     if (getCapitalCamel() != null) {
-      joiner.add(String.format("%sCapitalCamel%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getCapitalCamel()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sCapitalCamel%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getCapitalCamel()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `small_Snake` to the URL query string
     if (getSmallSnake() != null) {
-      joiner.add(String.format("%ssmall_Snake%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getSmallSnake()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%ssmall_Snake%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getSmallSnake()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `Capital_Snake` to the URL query string
     if (getCapitalSnake() != null) {
-      joiner.add(String.format("%sCapital_Snake%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getCapitalSnake()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sCapital_Snake%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getCapitalSnake()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `SCA_ETH_Flow_Points` to the URL query string
     if (getScAETHFlowPoints() != null) {
-      joiner.add(String.format("%sSCA_ETH_Flow_Points%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getScAETHFlowPoints()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sSCA_ETH_Flow_Points%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getScAETHFlowPoints()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `ATT_NAME` to the URL query string
     if (getATTNAME() != null) {
-      joiner.add(String.format("%sATT_NAME%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getATTNAME()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sATT_NAME%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getATTNAME()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Cat.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Cat.java
index 92d50dbb16..2e864543d1 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Cat.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Cat.java
@@ -34,6 +34,7 @@ import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
 import org.openapitools.client.JSON;
+import org.openapitools.client.ApiClient;
 /**
  * Cat
  */
@@ -167,17 +168,17 @@ public class Cat extends Animal {
 
     // add `className` to the URL query string
     if (getClassName() != null) {
-      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `color` to the URL query string
     if (getColor() != null) {
-      joiner.add(String.format("%scolor%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getColor()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%scolor%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getColor()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `declawed` to the URL query string
     if (getDeclawed() != null) {
-      joiner.add(String.format("%sdeclawed%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getDeclawed()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sdeclawed%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getDeclawed()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Category.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Category.java
index 7507e878e3..79f6d45f46 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Category.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Category.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Category
  */
@@ -172,12 +173,12 @@ public class Category {
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ChildCat.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ChildCat.java
index b7111332c9..0f7a12db15 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ChildCat.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ChildCat.java
@@ -35,6 +35,7 @@ import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
 import org.openapitools.client.JSON;
+import org.openapitools.client.ApiClient;
 /**
  * ChildCat
  */
@@ -199,12 +200,12 @@ public class ChildCat extends ParentPet {
 
     // add `pet_type` to the URL query string
     if (getPetType() != null) {
-      joiner.add(String.format("%spet_type%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPetType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%spet_type%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPetType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ClassModel.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ClassModel.java
index 1680ef0935..16061aa437 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ClassModel.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ClassModel.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Model for testing model with \&quot;_class\&quot; property
  */
@@ -141,7 +142,7 @@ public class ClassModel {
 
     // add `_class` to the URL query string
     if (getPropertyClass() != null) {
-      joiner.add(String.format("%s_class%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPropertyClass()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%s_class%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPropertyClass()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Client.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Client.java
index 04d0a72352..addebdc9f8 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Client.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Client.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Client
  */
@@ -141,7 +142,7 @@ public class Client {
 
     // add `client` to the URL query string
     if (getClient() != null) {
-      joiner.add(String.format("%sclient%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getClient()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sclient%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getClient()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ComplexQuadrilateral.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ComplexQuadrilateral.java
index 0c7134607c..8019326384 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ComplexQuadrilateral.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ComplexQuadrilateral.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * ComplexQuadrilateral
  */
@@ -172,12 +173,12 @@ public class ComplexQuadrilateral {
 
     // add `shapeType` to the URL query string
     if (getShapeType() != null) {
-      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `quadrilateralType` to the URL query string
     if (getQuadrilateralType() != null) {
-      joiner.add(String.format("%squadrilateralType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getQuadrilateralType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%squadrilateralType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getQuadrilateralType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/DanishPig.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/DanishPig.java
index 629ccb281d..ae622b263e 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/DanishPig.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/DanishPig.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * DanishPig
  */
@@ -141,7 +142,7 @@ public class DanishPig {
 
     // add `className` to the URL query string
     if (getClassName() != null) {
-      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/DeprecatedObject.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/DeprecatedObject.java
index 6872c7c60a..84903b0016 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/DeprecatedObject.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/DeprecatedObject.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * DeprecatedObject
  * @deprecated
@@ -143,7 +144,7 @@ public class DeprecatedObject {
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Dog.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Dog.java
index 6dc2d856e0..cae50d8150 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Dog.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Dog.java
@@ -33,6 +33,7 @@ import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
 import org.openapitools.client.JSON;
+import org.openapitools.client.ApiClient;
 /**
  * Dog
  */
@@ -166,17 +167,17 @@ public class Dog extends Animal {
 
     // add `className` to the URL query string
     if (getClassName() != null) {
-      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `color` to the URL query string
     if (getColor() != null) {
-      joiner.add(String.format("%scolor%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getColor()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%scolor%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getColor()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `breed` to the URL query string
     if (getBreed() != null) {
-      joiner.add(String.format("%sbreed%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getBreed()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sbreed%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getBreed()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Drawing.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Drawing.java
index 1131861814..feca125b3f 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Drawing.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Drawing.java
@@ -44,6 +44,7 @@ import java.util.NoSuchElementException;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Drawing
  */
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/EnumArrays.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/EnumArrays.java
index b513368172..6360fb0525 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/EnumArrays.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/EnumArrays.java
@@ -30,6 +30,7 @@ import java.util.List;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * EnumArrays
  */
@@ -252,7 +253,7 @@ public class EnumArrays {
 
     // add `just_symbol` to the URL query string
     if (getJustSymbol() != null) {
-      joiner.add(String.format("%sjust_symbol%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getJustSymbol()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sjust_symbol%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getJustSymbol()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `array_enum` to the URL query string
@@ -260,7 +261,7 @@ public class EnumArrays {
       for (int i = 0; i < getArrayEnum().size(); i++) {
         joiner.add(String.format("%sarray_enum%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getArrayEnum().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getArrayEnum().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/EnumTest.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/EnumTest.java
index 86abde19f7..d4fc6cadae 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/EnumTest.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/EnumTest.java
@@ -36,6 +36,7 @@ import java.util.NoSuchElementException;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * EnumTest
  */
@@ -595,47 +596,47 @@ public class EnumTest {
 
     // add `enum_string` to the URL query string
     if (getEnumString() != null) {
-      joiner.add(String.format("%senum_string%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getEnumString()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%senum_string%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getEnumString()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `enum_string_required` to the URL query string
     if (getEnumStringRequired() != null) {
-      joiner.add(String.format("%senum_string_required%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getEnumStringRequired()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%senum_string_required%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getEnumStringRequired()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `enum_integer` to the URL query string
     if (getEnumInteger() != null) {
-      joiner.add(String.format("%senum_integer%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getEnumInteger()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%senum_integer%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getEnumInteger()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `enum_integer_only` to the URL query string
     if (getEnumIntegerOnly() != null) {
-      joiner.add(String.format("%senum_integer_only%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getEnumIntegerOnly()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%senum_integer_only%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getEnumIntegerOnly()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `enum_number` to the URL query string
     if (getEnumNumber() != null) {
-      joiner.add(String.format("%senum_number%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getEnumNumber()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%senum_number%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getEnumNumber()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `outerEnum` to the URL query string
     if (getOuterEnum() != null) {
-      joiner.add(String.format("%souterEnum%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getOuterEnum()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%souterEnum%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getOuterEnum()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `outerEnumInteger` to the URL query string
     if (getOuterEnumInteger() != null) {
-      joiner.add(String.format("%souterEnumInteger%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getOuterEnumInteger()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%souterEnumInteger%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getOuterEnumInteger()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `outerEnumDefaultValue` to the URL query string
     if (getOuterEnumDefaultValue() != null) {
-      joiner.add(String.format("%souterEnumDefaultValue%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getOuterEnumDefaultValue()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%souterEnumDefaultValue%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getOuterEnumDefaultValue()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `outerEnumIntegerDefaultValue` to the URL query string
     if (getOuterEnumIntegerDefaultValue() != null) {
-      joiner.add(String.format("%souterEnumIntegerDefaultValue%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getOuterEnumIntegerDefaultValue()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%souterEnumIntegerDefaultValue%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getOuterEnumIntegerDefaultValue()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/EquilateralTriangle.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/EquilateralTriangle.java
index f5fa82474e..d61593d711 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/EquilateralTriangle.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/EquilateralTriangle.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * EquilateralTriangle
  */
@@ -172,12 +173,12 @@ public class EquilateralTriangle {
 
     // add `shapeType` to the URL query string
     if (getShapeType() != null) {
-      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `triangleType` to the URL query string
     if (getTriangleType() != null) {
-      joiner.add(String.format("%striangleType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getTriangleType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%striangleType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getTriangleType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/FakeBigDecimalMap200Response.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/FakeBigDecimalMap200Response.java
index 91156d7f18..3b906d17a0 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/FakeBigDecimalMap200Response.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/FakeBigDecimalMap200Response.java
@@ -31,6 +31,7 @@ import java.util.Map;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * FakeBigDecimalMap200Response
  */
@@ -183,7 +184,7 @@ public class FakeBigDecimalMap200Response {
 
     // add `someId` to the URL query string
     if (getSomeId() != null) {
-      joiner.add(String.format("%ssomeId%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getSomeId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%ssomeId%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getSomeId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `someMap` to the URL query string
@@ -191,7 +192,7 @@ public class FakeBigDecimalMap200Response {
       for (String _key : getSomeMap().keySet()) {
         joiner.add(String.format("%ssomeMap%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getSomeMap().get(_key), URLEncoder.encode(String.valueOf(getSomeMap().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getSomeMap().get(_key), URLEncoder.encode(ApiClient.valueToString(getSomeMap().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/FileSchemaTestClass.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/FileSchemaTestClass.java
index e5b34997ca..8286ab64c8 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/FileSchemaTestClass.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/FileSchemaTestClass.java
@@ -31,6 +31,7 @@ import org.openapitools.client.model.ModelFile;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * FileSchemaTestClass
  */
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Foo.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Foo.java
index 0f3f1be8f7..6b6d531388 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Foo.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Foo.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Foo
  */
@@ -141,7 +142,7 @@ public class Foo {
 
     // add `bar` to the URL query string
     if (getBar() != null) {
-      joiner.add(String.format("%sbar%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getBar()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sbar%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getBar()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/FooGetDefaultResponse.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/FooGetDefaultResponse.java
index 26f019b4fd..adad4fbfb5 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/FooGetDefaultResponse.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/FooGetDefaultResponse.java
@@ -29,6 +29,7 @@ import org.openapitools.client.model.Foo;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * FooGetDefaultResponse
  */
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/FormatTest.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/FormatTest.java
index 540bde2c86..335e9e31ef 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/FormatTest.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/FormatTest.java
@@ -33,6 +33,7 @@ import java.util.UUID;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * FormatTest
  */
@@ -621,82 +622,82 @@ public class FormatTest {
 
     // add `integer` to the URL query string
     if (getInteger() != null) {
-      joiner.add(String.format("%sinteger%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getInteger()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sinteger%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getInteger()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `int32` to the URL query string
     if (getInt32() != null) {
-      joiner.add(String.format("%sint32%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getInt32()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sint32%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getInt32()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `int64` to the URL query string
     if (getInt64() != null) {
-      joiner.add(String.format("%sint64%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getInt64()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sint64%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getInt64()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `number` to the URL query string
     if (getNumber() != null) {
-      joiner.add(String.format("%snumber%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getNumber()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%snumber%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getNumber()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `float` to the URL query string
     if (getFloat() != null) {
-      joiner.add(String.format("%sfloat%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getFloat()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sfloat%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getFloat()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `double` to the URL query string
     if (getDouble() != null) {
-      joiner.add(String.format("%sdouble%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getDouble()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sdouble%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getDouble()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `decimal` to the URL query string
     if (getDecimal() != null) {
-      joiner.add(String.format("%sdecimal%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getDecimal()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sdecimal%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getDecimal()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `string` to the URL query string
     if (getString() != null) {
-      joiner.add(String.format("%sstring%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getString()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sstring%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getString()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `byte` to the URL query string
     if (getByte() != null) {
-      joiner.add(String.format("%sbyte%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getByte()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sbyte%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getByte()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `binary` to the URL query string
     if (getBinary() != null) {
-      joiner.add(String.format("%sbinary%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getBinary()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sbinary%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getBinary()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `date` to the URL query string
     if (getDate() != null) {
-      joiner.add(String.format("%sdate%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getDate()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sdate%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getDate()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `dateTime` to the URL query string
     if (getDateTime() != null) {
-      joiner.add(String.format("%sdateTime%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getDateTime()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sdateTime%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getDateTime()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `uuid` to the URL query string
     if (getUuid() != null) {
-      joiner.add(String.format("%suuid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getUuid()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%suuid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getUuid()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `password` to the URL query string
     if (getPassword() != null) {
-      joiner.add(String.format("%spassword%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPassword()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%spassword%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPassword()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `pattern_with_digits` to the URL query string
     if (getPatternWithDigits() != null) {
-      joiner.add(String.format("%spattern_with_digits%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPatternWithDigits()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%spattern_with_digits%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPatternWithDigits()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `pattern_with_digits_and_delimiter` to the URL query string
     if (getPatternWithDigitsAndDelimiter() != null) {
-      joiner.add(String.format("%spattern_with_digits_and_delimiter%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPatternWithDigitsAndDelimiter()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%spattern_with_digits_and_delimiter%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPatternWithDigitsAndDelimiter()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/GrandparentAnimal.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/GrandparentAnimal.java
index f24bcad1ec..978e139e58 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/GrandparentAnimal.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/GrandparentAnimal.java
@@ -32,6 +32,7 @@ import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
 import org.openapitools.client.JSON;
+import org.openapitools.client.ApiClient;
 /**
  * GrandparentAnimal
  */
@@ -155,7 +156,7 @@ public class GrandparentAnimal {
 
     // add `pet_type` to the URL query string
     if (getPetType() != null) {
-      joiner.add(String.format("%spet_type%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPetType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%spet_type%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPetType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/HasOnlyReadOnly.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/HasOnlyReadOnly.java
index 3de0f7311d..147bab1ec6 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/HasOnlyReadOnly.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/HasOnlyReadOnly.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * HasOnlyReadOnly
  */
@@ -162,12 +163,12 @@ public class HasOnlyReadOnly {
 
     // add `bar` to the URL query string
     if (getBar() != null) {
-      joiner.add(String.format("%sbar%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getBar()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sbar%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getBar()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `foo` to the URL query string
     if (getFoo() != null) {
-      joiner.add(String.format("%sfoo%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getFoo()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sfoo%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getFoo()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/HealthCheckResult.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/HealthCheckResult.java
index c707f2b4ee..7af7a9cf3b 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/HealthCheckResult.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/HealthCheckResult.java
@@ -32,6 +32,7 @@ import java.util.NoSuchElementException;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Just a string to inform instance is up and running. Make it nullable in hope to get it as pointer in generated model.
  */
@@ -164,7 +165,7 @@ public class HealthCheckResult {
 
     // add `NullableMessage` to the URL query string
     if (getNullableMessage() != null) {
-      joiner.add(String.format("%sNullableMessage%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getNullableMessage()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sNullableMessage%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getNullableMessage()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/IsoscelesTriangle.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/IsoscelesTriangle.java
index 4efe720c84..08daaf932b 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/IsoscelesTriangle.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/IsoscelesTriangle.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * IsoscelesTriangle
  */
@@ -172,12 +173,12 @@ public class IsoscelesTriangle {
 
     // add `shapeType` to the URL query string
     if (getShapeType() != null) {
-      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `triangleType` to the URL query string
     if (getTriangleType() != null) {
-      joiner.add(String.format("%striangleType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getTriangleType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%striangleType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getTriangleType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/MapTest.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/MapTest.java
index d0232ef777..1e47edc6a1 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/MapTest.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/MapTest.java
@@ -30,6 +30,7 @@ import java.util.Map;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * MapTest
  */
@@ -306,7 +307,7 @@ public class MapTest {
       for (String _key : getMapMapOfString().keySet()) {
         joiner.add(String.format("%smap_map_of_string%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getMapMapOfString().get(_key), URLEncoder.encode(String.valueOf(getMapMapOfString().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getMapMapOfString().get(_key), URLEncoder.encode(ApiClient.valueToString(getMapMapOfString().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -315,7 +316,7 @@ public class MapTest {
       for (String _key : getMapOfEnumString().keySet()) {
         joiner.add(String.format("%smap_of_enum_string%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getMapOfEnumString().get(_key), URLEncoder.encode(String.valueOf(getMapOfEnumString().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getMapOfEnumString().get(_key), URLEncoder.encode(ApiClient.valueToString(getMapOfEnumString().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -324,7 +325,7 @@ public class MapTest {
       for (String _key : getDirectMap().keySet()) {
         joiner.add(String.format("%sdirect_map%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getDirectMap().get(_key), URLEncoder.encode(String.valueOf(getDirectMap().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getDirectMap().get(_key), URLEncoder.encode(ApiClient.valueToString(getDirectMap().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -333,7 +334,7 @@ public class MapTest {
       for (String _key : getIndirectMap().keySet()) {
         joiner.add(String.format("%sindirect_map%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getIndirectMap().get(_key), URLEncoder.encode(String.valueOf(getIndirectMap().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getIndirectMap().get(_key), URLEncoder.encode(ApiClient.valueToString(getIndirectMap().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/MixedPropertiesAndAdditionalPropertiesClass.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/MixedPropertiesAndAdditionalPropertiesClass.java
index f23064aa14..a7dce3b745 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/MixedPropertiesAndAdditionalPropertiesClass.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/MixedPropertiesAndAdditionalPropertiesClass.java
@@ -33,6 +33,7 @@ import org.openapitools.client.model.Animal;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * MixedPropertiesAndAdditionalPropertiesClass
  */
@@ -216,12 +217,12 @@ public class MixedPropertiesAndAdditionalPropertiesClass {
 
     // add `uuid` to the URL query string
     if (getUuid() != null) {
-      joiner.add(String.format("%suuid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getUuid()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%suuid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getUuid()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `dateTime` to the URL query string
     if (getDateTime() != null) {
-      joiner.add(String.format("%sdateTime%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getDateTime()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sdateTime%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getDateTime()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `map` to the URL query string
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Model200Response.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Model200Response.java
index 77f5caa390..b3451d48b5 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Model200Response.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Model200Response.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Model for testing model name starting with number
  */
@@ -172,12 +173,12 @@ public class Model200Response {
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `class` to the URL query string
     if (getPropertyClass() != null) {
-      joiner.add(String.format("%sclass%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPropertyClass()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sclass%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPropertyClass()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ModelApiResponse.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ModelApiResponse.java
index 994dbd0c51..24f5219d19 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ModelApiResponse.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ModelApiResponse.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * ModelApiResponse
  */
@@ -203,17 +204,17 @@ public class ModelApiResponse {
 
     // add `code` to the URL query string
     if (getCode() != null) {
-      joiner.add(String.format("%scode%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getCode()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%scode%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getCode()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `type` to the URL query string
     if (getType() != null) {
-      joiner.add(String.format("%stype%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%stype%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `message` to the URL query string
     if (getMessage() != null) {
-      joiner.add(String.format("%smessage%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getMessage()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%smessage%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getMessage()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ModelFile.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ModelFile.java
index f046f0f944..f687543faf 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ModelFile.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ModelFile.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Must be named &#x60;File&#x60; for test.
  */
@@ -141,7 +142,7 @@ public class ModelFile {
 
     // add `sourceURI` to the URL query string
     if (getSourceURI() != null) {
-      joiner.add(String.format("%ssourceURI%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getSourceURI()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%ssourceURI%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getSourceURI()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ModelList.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ModelList.java
index b567f27fa2..90998395ec 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ModelList.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ModelList.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * ModelList
  */
@@ -141,7 +142,7 @@ public class ModelList {
 
     // add `123-list` to the URL query string
     if (get123list() != null) {
-      joiner.add(String.format("%s123-list%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(get123list()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%s123-list%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(get123list()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ModelReturn.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ModelReturn.java
index f251d2f379..efcb0bdf0b 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ModelReturn.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ModelReturn.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Model for testing reserved words
  */
@@ -141,7 +142,7 @@ public class ModelReturn {
 
     // add `return` to the URL query string
     if (getReturn() != null) {
-      joiner.add(String.format("%sreturn%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getReturn()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sreturn%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getReturn()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Name.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Name.java
index 333ce82e36..67885182db 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Name.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Name.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Model for testing model name same as property name
  */
@@ -224,22 +225,22 @@ public class Name {
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `snake_case` to the URL query string
     if (getSnakeCase() != null) {
-      joiner.add(String.format("%ssnake_case%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getSnakeCase()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%ssnake_case%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getSnakeCase()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `property` to the URL query string
     if (getProperty() != null) {
-      joiner.add(String.format("%sproperty%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getProperty()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sproperty%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getProperty()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `123Number` to the URL query string
     if (get123number() != null) {
-      joiner.add(String.format("%s123Number%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(get123number()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%s123Number%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(get123number()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/NullableClass.java
index 4826e81821..aa0e2791c1 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -43,6 +43,7 @@ import java.util.NoSuchElementException;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * NullableClass
  */
@@ -699,32 +700,32 @@ public class NullableClass extends HashMap<String, Object> {
 
     // add `integer_prop` to the URL query string
     if (getIntegerProp() != null) {
-      joiner.add(String.format("%sinteger_prop%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getIntegerProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sinteger_prop%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getIntegerProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `number_prop` to the URL query string
     if (getNumberProp() != null) {
-      joiner.add(String.format("%snumber_prop%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getNumberProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%snumber_prop%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getNumberProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `boolean_prop` to the URL query string
     if (getBooleanProp() != null) {
-      joiner.add(String.format("%sboolean_prop%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getBooleanProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sboolean_prop%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getBooleanProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `string_prop` to the URL query string
     if (getStringProp() != null) {
-      joiner.add(String.format("%sstring_prop%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getStringProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sstring_prop%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getStringProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `date_prop` to the URL query string
     if (getDateProp() != null) {
-      joiner.add(String.format("%sdate_prop%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getDateProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sdate_prop%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getDateProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `datetime_prop` to the URL query string
     if (getDatetimeProp() != null) {
-      joiner.add(String.format("%sdatetime_prop%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getDatetimeProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sdatetime_prop%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getDatetimeProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `array_nullable_prop` to the URL query string
@@ -732,7 +733,7 @@ public class NullableClass extends HashMap<String, Object> {
       for (int i = 0; i < getArrayNullableProp().size(); i++) {
         joiner.add(String.format("%sarray_nullable_prop%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getArrayNullableProp().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getArrayNullableProp().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -741,7 +742,7 @@ public class NullableClass extends HashMap<String, Object> {
       for (int i = 0; i < getArrayAndItemsNullableProp().size(); i++) {
         joiner.add(String.format("%sarray_and_items_nullable_prop%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getArrayAndItemsNullableProp().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getArrayAndItemsNullableProp().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -750,7 +751,7 @@ public class NullableClass extends HashMap<String, Object> {
       for (int i = 0; i < getArrayItemsNullable().size(); i++) {
         joiner.add(String.format("%sarray_items_nullable%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getArrayItemsNullable().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getArrayItemsNullable().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -759,7 +760,7 @@ public class NullableClass extends HashMap<String, Object> {
       for (String _key : getObjectNullableProp().keySet()) {
         joiner.add(String.format("%sobject_nullable_prop%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getObjectNullableProp().get(_key), URLEncoder.encode(String.valueOf(getObjectNullableProp().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getObjectNullableProp().get(_key), URLEncoder.encode(ApiClient.valueToString(getObjectNullableProp().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -768,7 +769,7 @@ public class NullableClass extends HashMap<String, Object> {
       for (String _key : getObjectAndItemsNullableProp().keySet()) {
         joiner.add(String.format("%sobject_and_items_nullable_prop%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getObjectAndItemsNullableProp().get(_key), URLEncoder.encode(String.valueOf(getObjectAndItemsNullableProp().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getObjectAndItemsNullableProp().get(_key), URLEncoder.encode(ApiClient.valueToString(getObjectAndItemsNullableProp().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -777,7 +778,7 @@ public class NullableClass extends HashMap<String, Object> {
       for (String _key : getObjectItemsNullable().keySet()) {
         joiner.add(String.format("%sobject_items_nullable%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getObjectItemsNullable().get(_key), URLEncoder.encode(String.valueOf(getObjectItemsNullable().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getObjectItemsNullable().get(_key), URLEncoder.encode(ApiClient.valueToString(getObjectItemsNullable().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/NumberOnly.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/NumberOnly.java
index 25878e78f3..ab57aa2132 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/NumberOnly.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/NumberOnly.java
@@ -29,6 +29,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * NumberOnly
  */
@@ -142,7 +143,7 @@ public class NumberOnly {
 
     // add `JustNumber` to the URL query string
     if (getJustNumber() != null) {
-      joiner.add(String.format("%sJustNumber%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getJustNumber()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sJustNumber%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getJustNumber()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ObjectWithDeprecatedFields.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ObjectWithDeprecatedFields.java
index 9706ad66c0..589328d9b5 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ObjectWithDeprecatedFields.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ObjectWithDeprecatedFields.java
@@ -32,6 +32,7 @@ import org.openapitools.client.model.DeprecatedObject;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * ObjectWithDeprecatedFields
  */
@@ -252,12 +253,12 @@ public class ObjectWithDeprecatedFields {
 
     // add `uuid` to the URL query string
     if (getUuid() != null) {
-      joiner.add(String.format("%suuid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getUuid()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%suuid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getUuid()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `deprecatedRef` to the URL query string
@@ -270,7 +271,7 @@ public class ObjectWithDeprecatedFields {
       for (int i = 0; i < getBars().size(); i++) {
         joiner.add(String.format("%sbars%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getBars().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getBars().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Order.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Order.java
index 188f32191b..8e82b7c362 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Order.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Order.java
@@ -29,6 +29,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Order
  */
@@ -334,32 +335,32 @@ public class Order {
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `petId` to the URL query string
     if (getPetId() != null) {
-      joiner.add(String.format("%spetId%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPetId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%spetId%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPetId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `quantity` to the URL query string
     if (getQuantity() != null) {
-      joiner.add(String.format("%squantity%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getQuantity()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%squantity%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getQuantity()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `shipDate` to the URL query string
     if (getShipDate() != null) {
-      joiner.add(String.format("%sshipDate%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getShipDate()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sshipDate%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getShipDate()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `status` to the URL query string
     if (getStatus() != null) {
-      joiner.add(String.format("%sstatus%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getStatus()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sstatus%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getStatus()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `complete` to the URL query string
     if (getComplete() != null) {
-      joiner.add(String.format("%scomplete%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getComplete()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%scomplete%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getComplete()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/OuterComposite.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/OuterComposite.java
index 7478045b9e..71c635222e 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/OuterComposite.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/OuterComposite.java
@@ -29,6 +29,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * OuterComposite
  */
@@ -204,17 +205,17 @@ public class OuterComposite {
 
     // add `my_number` to the URL query string
     if (getMyNumber() != null) {
-      joiner.add(String.format("%smy_number%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getMyNumber()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%smy_number%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getMyNumber()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `my_string` to the URL query string
     if (getMyString() != null) {
-      joiner.add(String.format("%smy_string%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getMyString()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%smy_string%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getMyString()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `my_boolean` to the URL query string
     if (getMyBoolean() != null) {
-      joiner.add(String.format("%smy_boolean%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getMyBoolean()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%smy_boolean%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getMyBoolean()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ParentPet.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ParentPet.java
index 9f4030b69e..499a149d75 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ParentPet.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ParentPet.java
@@ -33,6 +33,7 @@ import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
 import org.openapitools.client.JSON;
+import org.openapitools.client.ApiClient;
 /**
  * ParentPet
  */
@@ -131,7 +132,7 @@ public class ParentPet extends GrandparentAnimal {
 
     // add `pet_type` to the URL query string
     if (getPetType() != null) {
-      joiner.add(String.format("%spet_type%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPetType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%spet_type%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPetType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Pet.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Pet.java
index 05f0df5a4c..b6d82d5e38 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Pet.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Pet.java
@@ -32,6 +32,7 @@ import org.openapitools.client.model.Tag;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Pet
  */
@@ -353,7 +354,7 @@ public class Pet {
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `category` to the URL query string
@@ -363,7 +364,7 @@ public class Pet {
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `photoUrls` to the URL query string
@@ -371,7 +372,7 @@ public class Pet {
       for (int i = 0; i < getPhotoUrls().size(); i++) {
         joiner.add(String.format("%sphotoUrls%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getPhotoUrls().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getPhotoUrls().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -387,7 +388,7 @@ public class Pet {
 
     // add `status` to the URL query string
     if (getStatus() != null) {
-      joiner.add(String.format("%sstatus%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getStatus()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sstatus%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getStatus()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/QuadrilateralInterface.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/QuadrilateralInterface.java
index f476664aca..af070c76bb 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/QuadrilateralInterface.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/QuadrilateralInterface.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * QuadrilateralInterface
  */
@@ -141,7 +142,7 @@ public class QuadrilateralInterface {
 
     // add `quadrilateralType` to the URL query string
     if (getQuadrilateralType() != null) {
-      joiner.add(String.format("%squadrilateralType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getQuadrilateralType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%squadrilateralType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getQuadrilateralType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ReadOnlyFirst.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ReadOnlyFirst.java
index 88a0db6a57..63b6b5b629 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ReadOnlyFirst.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ReadOnlyFirst.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * ReadOnlyFirst
  */
@@ -170,12 +171,12 @@ public class ReadOnlyFirst {
 
     // add `bar` to the URL query string
     if (getBar() != null) {
-      joiner.add(String.format("%sbar%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getBar()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sbar%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getBar()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `baz` to the URL query string
     if (getBaz() != null) {
-      joiner.add(String.format("%sbaz%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getBaz()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sbaz%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getBaz()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ScaleneTriangle.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ScaleneTriangle.java
index 01697f6041..6bce242d09 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ScaleneTriangle.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ScaleneTriangle.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * ScaleneTriangle
  */
@@ -172,12 +173,12 @@ public class ScaleneTriangle {
 
     // add `shapeType` to the URL query string
     if (getShapeType() != null) {
-      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `triangleType` to the URL query string
     if (getTriangleType() != null) {
-      joiner.add(String.format("%striangleType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getTriangleType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%striangleType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getTriangleType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ShapeInterface.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ShapeInterface.java
index 6d8982eb72..ec1d70b017 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ShapeInterface.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/ShapeInterface.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * ShapeInterface
  */
@@ -141,7 +142,7 @@ public class ShapeInterface {
 
     // add `shapeType` to the URL query string
     if (getShapeType() != null) {
-      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/SimpleQuadrilateral.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/SimpleQuadrilateral.java
index 9585153dc7..226f8fa21e 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/SimpleQuadrilateral.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/SimpleQuadrilateral.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * SimpleQuadrilateral
  */
@@ -172,12 +173,12 @@ public class SimpleQuadrilateral {
 
     // add `shapeType` to the URL query string
     if (getShapeType() != null) {
-      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `quadrilateralType` to the URL query string
     if (getQuadrilateralType() != null) {
-      joiner.add(String.format("%squadrilateralType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getQuadrilateralType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%squadrilateralType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getQuadrilateralType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/SpecialModelName.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/SpecialModelName.java
index b35be7f578..8cdcb52f64 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/SpecialModelName.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/SpecialModelName.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * SpecialModelName
  */
@@ -172,12 +173,12 @@ public class SpecialModelName {
 
     // add `$special[property.name]` to the URL query string
     if (get$SpecialPropertyName() != null) {
-      joiner.add(String.format("%s$special[property.name]%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(get$SpecialPropertyName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%s$special[property.name]%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(get$SpecialPropertyName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `_special_model.name_` to the URL query string
     if (getSpecialModelName() != null) {
-      joiner.add(String.format("%s_special_model.name_%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getSpecialModelName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%s_special_model.name_%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getSpecialModelName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Tag.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Tag.java
index 19f5584b2c..84ac9e813c 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Tag.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Tag.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Tag
  */
@@ -172,12 +173,12 @@ public class Tag {
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/TestInlineFreeformAdditionalPropertiesRequest.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/TestInlineFreeformAdditionalPropertiesRequest.java
index ef8727d99e..6c8770f1fb 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/TestInlineFreeformAdditionalPropertiesRequest.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/TestInlineFreeformAdditionalPropertiesRequest.java
@@ -34,6 +34,7 @@ import java.util.Map;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * TestInlineFreeformAdditionalPropertiesRequest
  */
@@ -194,7 +195,7 @@ public class TestInlineFreeformAdditionalPropertiesRequest extends HashMap<Strin
 
     // add `someProperty` to the URL query string
     if (getSomeProperty() != null) {
-      joiner.add(String.format("%ssomeProperty%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getSomeProperty()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%ssomeProperty%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getSomeProperty()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/TriangleInterface.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/TriangleInterface.java
index b5f454ba64..b0a3e0ca9d 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/TriangleInterface.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/TriangleInterface.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * TriangleInterface
  */
@@ -141,7 +142,7 @@ public class TriangleInterface {
 
     // add `triangleType` to the URL query string
     if (getTriangleType() != null) {
-      joiner.add(String.format("%striangleType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getTriangleType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%striangleType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getTriangleType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/User.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/User.java
index d7a804ae48..8b5c7dbf77 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/User.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/User.java
@@ -32,6 +32,7 @@ import java.util.NoSuchElementException;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * User
  */
@@ -521,62 +522,62 @@ public class User {
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `username` to the URL query string
     if (getUsername() != null) {
-      joiner.add(String.format("%susername%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getUsername()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%susername%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getUsername()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `firstName` to the URL query string
     if (getFirstName() != null) {
-      joiner.add(String.format("%sfirstName%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getFirstName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sfirstName%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getFirstName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `lastName` to the URL query string
     if (getLastName() != null) {
-      joiner.add(String.format("%slastName%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getLastName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%slastName%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getLastName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `email` to the URL query string
     if (getEmail() != null) {
-      joiner.add(String.format("%semail%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getEmail()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%semail%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getEmail()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `password` to the URL query string
     if (getPassword() != null) {
-      joiner.add(String.format("%spassword%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPassword()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%spassword%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPassword()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `phone` to the URL query string
     if (getPhone() != null) {
-      joiner.add(String.format("%sphone%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPhone()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sphone%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPhone()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `userStatus` to the URL query string
     if (getUserStatus() != null) {
-      joiner.add(String.format("%suserStatus%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getUserStatus()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%suserStatus%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getUserStatus()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `objectWithNoDeclaredProps` to the URL query string
     if (getObjectWithNoDeclaredProps() != null) {
-      joiner.add(String.format("%sobjectWithNoDeclaredProps%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getObjectWithNoDeclaredProps()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sobjectWithNoDeclaredProps%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getObjectWithNoDeclaredProps()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `objectWithNoDeclaredPropsNullable` to the URL query string
     if (getObjectWithNoDeclaredPropsNullable() != null) {
-      joiner.add(String.format("%sobjectWithNoDeclaredPropsNullable%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getObjectWithNoDeclaredPropsNullable()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sobjectWithNoDeclaredPropsNullable%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getObjectWithNoDeclaredPropsNullable()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `anyTypeProp` to the URL query string
     if (getAnyTypeProp() != null) {
-      joiner.add(String.format("%sanyTypeProp%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getAnyTypeProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sanyTypeProp%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getAnyTypeProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `anyTypePropNullable` to the URL query string
     if (getAnyTypePropNullable() != null) {
-      joiner.add(String.format("%sanyTypePropNullable%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getAnyTypePropNullable()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sanyTypePropNullable%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getAnyTypePropNullable()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Whale.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Whale.java
index fec2863320..cff95aae26 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Whale.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Whale.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Whale
  */
@@ -203,17 +204,17 @@ public class Whale {
 
     // add `hasBaleen` to the URL query string
     if (getHasBaleen() != null) {
-      joiner.add(String.format("%shasBaleen%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getHasBaleen()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%shasBaleen%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getHasBaleen()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `hasTeeth` to the URL query string
     if (getHasTeeth() != null) {
-      joiner.add(String.format("%shasTeeth%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getHasTeeth()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%shasTeeth%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getHasTeeth()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `className` to the URL query string
     if (getClassName() != null) {
-      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Zebra.java b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Zebra.java
index 1d1ad24cd0..d09e3ea97f 100644
--- a/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Zebra.java
+++ b/samples/client/petstore/java/native-async/src/main/java/org/openapitools/client/model/Zebra.java
@@ -34,6 +34,7 @@ import java.util.Map;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Zebra
  */
@@ -262,12 +263,12 @@ public class Zebra extends HashMap<String, Object> {
 
     // add `type` to the URL query string
     if (getType() != null) {
-      joiner.add(String.format("%stype%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%stype%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `className` to the URL query string
     if (getClassName() != null) {
-      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/ApiClient.java
index 2c4d36e0ec..ee175d06ae 100644
--- a/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/ApiClient.java
@@ -66,7 +66,7 @@ public class ApiClient {
   private Duration readTimeout;
   private Duration connectTimeout;
 
-  private static String valueToString(Object value) {
+  public static String valueToString(Object value) {
     if (value == null) {
       return "";
     }
diff --git a/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/Category.java b/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/Category.java
index def25a01e4..f95377e03a 100644
--- a/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/Category.java
+++ b/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/Category.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * A category for a pet
  */
@@ -172,12 +173,12 @@ public class Category {
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/ModelApiResponse.java b/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/ModelApiResponse.java
index 787bf40a78..d8e2cef264 100644
--- a/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/ModelApiResponse.java
+++ b/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/ModelApiResponse.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Describes the result of uploading an image resource
  */
@@ -203,17 +204,17 @@ public class ModelApiResponse {
 
     // add `code` to the URL query string
     if (getCode() != null) {
-      joiner.add(String.format("%scode%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getCode()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%scode%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getCode()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `type` to the URL query string
     if (getType() != null) {
-      joiner.add(String.format("%stype%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%stype%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `message` to the URL query string
     if (getMessage() != null) {
-      joiner.add(String.format("%smessage%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getMessage()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%smessage%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getMessage()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/Order.java b/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/Order.java
index 5dce58fe71..01ce02aefb 100644
--- a/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/Order.java
+++ b/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/Order.java
@@ -29,6 +29,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * An order for a pets from the pet store
  */
@@ -334,32 +335,32 @@ public class Order {
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `petId` to the URL query string
     if (getPetId() != null) {
-      joiner.add(String.format("%spetId%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPetId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%spetId%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPetId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `quantity` to the URL query string
     if (getQuantity() != null) {
-      joiner.add(String.format("%squantity%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getQuantity()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%squantity%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getQuantity()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `shipDate` to the URL query string
     if (getShipDate() != null) {
-      joiner.add(String.format("%sshipDate%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getShipDate()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sshipDate%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getShipDate()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `status` to the URL query string
     if (getStatus() != null) {
-      joiner.add(String.format("%sstatus%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getStatus()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sstatus%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getStatus()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `complete` to the URL query string
     if (getComplete() != null) {
-      joiner.add(String.format("%scomplete%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getComplete()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%scomplete%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getComplete()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/Pet.java b/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/Pet.java
index 8ca455742a..03d29c5ebd 100644
--- a/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/Pet.java
+++ b/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/Pet.java
@@ -32,6 +32,7 @@ import org.openapitools.client.model.Tag;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * A pet for sale in the pet store
  */
@@ -355,7 +356,7 @@ public class Pet {
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `category` to the URL query string
@@ -365,7 +366,7 @@ public class Pet {
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `photoUrls` to the URL query string
@@ -373,7 +374,7 @@ public class Pet {
       for (int i = 0; i < getPhotoUrls().size(); i++) {
         joiner.add(String.format("%sphotoUrls%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getPhotoUrls().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getPhotoUrls().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -389,7 +390,7 @@ public class Pet {
 
     // add `status` to the URL query string
     if (getStatus() != null) {
-      joiner.add(String.format("%sstatus%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getStatus()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sstatus%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getStatus()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/Tag.java b/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/Tag.java
index dd051c8e65..694b9f3643 100644
--- a/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/Tag.java
+++ b/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/Tag.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * A tag for a pet
  */
@@ -172,12 +173,12 @@ public class Tag {
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/User.java b/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/User.java
index 3359458b7e..31c9aefd55 100644
--- a/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/User.java
+++ b/samples/client/petstore/java/native-jakarta/src/main/java/org/openapitools/client/model/User.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * A User who is purchasing from the pet store
  */
@@ -358,42 +359,42 @@ public class User {
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `username` to the URL query string
     if (getUsername() != null) {
-      joiner.add(String.format("%susername%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getUsername()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%susername%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getUsername()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `firstName` to the URL query string
     if (getFirstName() != null) {
-      joiner.add(String.format("%sfirstName%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getFirstName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sfirstName%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getFirstName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `lastName` to the URL query string
     if (getLastName() != null) {
-      joiner.add(String.format("%slastName%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getLastName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%slastName%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getLastName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `email` to the URL query string
     if (getEmail() != null) {
-      joiner.add(String.format("%semail%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getEmail()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%semail%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getEmail()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `password` to the URL query string
     if (getPassword() != null) {
-      joiner.add(String.format("%spassword%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPassword()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%spassword%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPassword()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `phone` to the URL query string
     if (getPhone() != null) {
-      joiner.add(String.format("%sphone%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPhone()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sphone%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPhone()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `userStatus` to the URL query string
     if (getUserStatus() != null) {
-      joiner.add(String.format("%suserStatus%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getUserStatus()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%suserStatus%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getUserStatus()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/ApiClient.java
index 492e9aea50..6092094f1b 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/ApiClient.java
@@ -66,7 +66,7 @@ public class ApiClient {
   private Duration readTimeout;
   private Duration connectTimeout;
 
-  private static String valueToString(Object value) {
+  public static String valueToString(Object value) {
     if (value == null) {
       return "";
     }
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/AdditionalPropertiesClass.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/AdditionalPropertiesClass.java
index ee4b7d5113..156e833b68 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/AdditionalPropertiesClass.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/AdditionalPropertiesClass.java
@@ -34,6 +34,7 @@ import java.util.NoSuchElementException;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * AdditionalPropertiesClass
  */
@@ -418,7 +419,7 @@ public class AdditionalPropertiesClass {
       for (String _key : getMapProperty().keySet()) {
         joiner.add(String.format("%smap_property%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getMapProperty().get(_key), URLEncoder.encode(String.valueOf(getMapProperty().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getMapProperty().get(_key), URLEncoder.encode(ApiClient.valueToString(getMapProperty().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -427,23 +428,23 @@ public class AdditionalPropertiesClass {
       for (String _key : getMapOfMapProperty().keySet()) {
         joiner.add(String.format("%smap_of_map_property%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getMapOfMapProperty().get(_key), URLEncoder.encode(String.valueOf(getMapOfMapProperty().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getMapOfMapProperty().get(_key), URLEncoder.encode(ApiClient.valueToString(getMapOfMapProperty().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
     // add `anytype_1` to the URL query string
     if (getAnytype1() != null) {
-      joiner.add(String.format("%sanytype_1%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getAnytype1()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sanytype_1%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getAnytype1()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `map_with_undeclared_properties_anytype_1` to the URL query string
     if (getMapWithUndeclaredPropertiesAnytype1() != null) {
-      joiner.add(String.format("%smap_with_undeclared_properties_anytype_1%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getMapWithUndeclaredPropertiesAnytype1()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%smap_with_undeclared_properties_anytype_1%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getMapWithUndeclaredPropertiesAnytype1()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `map_with_undeclared_properties_anytype_2` to the URL query string
     if (getMapWithUndeclaredPropertiesAnytype2() != null) {
-      joiner.add(String.format("%smap_with_undeclared_properties_anytype_2%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getMapWithUndeclaredPropertiesAnytype2()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%smap_with_undeclared_properties_anytype_2%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getMapWithUndeclaredPropertiesAnytype2()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `map_with_undeclared_properties_anytype_3` to the URL query string
@@ -451,13 +452,13 @@ public class AdditionalPropertiesClass {
       for (String _key : getMapWithUndeclaredPropertiesAnytype3().keySet()) {
         joiner.add(String.format("%smap_with_undeclared_properties_anytype_3%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getMapWithUndeclaredPropertiesAnytype3().get(_key), URLEncoder.encode(String.valueOf(getMapWithUndeclaredPropertiesAnytype3().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getMapWithUndeclaredPropertiesAnytype3().get(_key), URLEncoder.encode(ApiClient.valueToString(getMapWithUndeclaredPropertiesAnytype3().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
     // add `empty_map` to the URL query string
     if (getEmptyMap() != null) {
-      joiner.add(String.format("%sempty_map%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getEmptyMap()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sempty_map%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getEmptyMap()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `map_with_undeclared_properties_string` to the URL query string
@@ -465,7 +466,7 @@ public class AdditionalPropertiesClass {
       for (String _key : getMapWithUndeclaredPropertiesString().keySet()) {
         joiner.add(String.format("%smap_with_undeclared_properties_string%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getMapWithUndeclaredPropertiesString().get(_key), URLEncoder.encode(String.valueOf(getMapWithUndeclaredPropertiesString().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getMapWithUndeclaredPropertiesString().get(_key), URLEncoder.encode(ApiClient.valueToString(getMapWithUndeclaredPropertiesString().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Animal.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Animal.java
index 0c79a6530f..9c91504057 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Animal.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Animal.java
@@ -32,6 +32,7 @@ import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
 import org.openapitools.client.JSON;
+import org.openapitools.client.ApiClient;
 /**
  * Animal
  */
@@ -186,12 +187,12 @@ public class Animal {
 
     // add `className` to the URL query string
     if (getClassName() != null) {
-      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `color` to the URL query string
     if (getColor() != null) {
-      joiner.add(String.format("%scolor%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getColor()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%scolor%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getColor()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Apple.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Apple.java
index c33a126ad2..2b347a813e 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Apple.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Apple.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Apple
  */
@@ -172,12 +173,12 @@ public class Apple {
 
     // add `cultivar` to the URL query string
     if (getCultivar() != null) {
-      joiner.add(String.format("%scultivar%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getCultivar()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%scultivar%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getCultivar()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `origin` to the URL query string
     if (getOrigin() != null) {
-      joiner.add(String.format("%sorigin%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getOrigin()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sorigin%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getOrigin()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/AppleReq.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/AppleReq.java
index 58aecfa69e..36c5a1239c 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/AppleReq.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/AppleReq.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * AppleReq
  */
@@ -172,12 +173,12 @@ public class AppleReq {
 
     // add `cultivar` to the URL query string
     if (getCultivar() != null) {
-      joiner.add(String.format("%scultivar%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getCultivar()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%scultivar%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getCultivar()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `mealy` to the URL query string
     if (getMealy() != null) {
-      joiner.add(String.format("%smealy%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getMealy()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%smealy%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getMealy()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ArrayOfArrayOfNumberOnly.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ArrayOfArrayOfNumberOnly.java
index 2d44cc2cd1..3f9bcb7600 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ArrayOfArrayOfNumberOnly.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ArrayOfArrayOfNumberOnly.java
@@ -31,6 +31,7 @@ import java.util.List;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * ArrayOfArrayOfNumberOnly
  */
@@ -156,7 +157,7 @@ public class ArrayOfArrayOfNumberOnly {
         if (getArrayArrayNumber().get(i) != null) {
           joiner.add(String.format("%sArrayArrayNumber%s%s=%s", prefix, suffix,
               "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-              URLEncoder.encode(String.valueOf(getArrayArrayNumber().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+              URLEncoder.encode(ApiClient.valueToString(getArrayArrayNumber().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
         }
       }
     }
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ArrayOfNumberOnly.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ArrayOfNumberOnly.java
index f656e61ecb..2497ce10cf 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ArrayOfNumberOnly.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ArrayOfNumberOnly.java
@@ -31,6 +31,7 @@ import java.util.List;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * ArrayOfNumberOnly
  */
@@ -156,7 +157,7 @@ public class ArrayOfNumberOnly {
         if (getArrayNumber().get(i) != null) {
           joiner.add(String.format("%sArrayNumber%s%s=%s", prefix, suffix,
               "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-              URLEncoder.encode(String.valueOf(getArrayNumber().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+              URLEncoder.encode(ApiClient.valueToString(getArrayNumber().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
         }
       }
     }
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ArrayTest.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ArrayTest.java
index f8c7029a24..c3c1ac9e9a 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ArrayTest.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ArrayTest.java
@@ -31,6 +31,7 @@ import org.openapitools.client.model.ReadOnlyFirst;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * ArrayTest
  */
@@ -233,7 +234,7 @@ public class ArrayTest {
       for (int i = 0; i < getArrayOfString().size(); i++) {
         joiner.add(String.format("%sarray_of_string%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getArrayOfString().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getArrayOfString().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -242,7 +243,7 @@ public class ArrayTest {
       for (int i = 0; i < getArrayArrayOfInteger().size(); i++) {
         joiner.add(String.format("%sarray_array_of_integer%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getArrayArrayOfInteger().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getArrayArrayOfInteger().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -252,7 +253,7 @@ public class ArrayTest {
         if (getArrayArrayOfModel().get(i) != null) {
           joiner.add(String.format("%sarray_array_of_model%s%s=%s", prefix, suffix,
               "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-              URLEncoder.encode(String.valueOf(getArrayArrayOfModel().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+              URLEncoder.encode(ApiClient.valueToString(getArrayArrayOfModel().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
         }
       }
     }
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Banana.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Banana.java
index 8baaaa0137..46668a213f 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Banana.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Banana.java
@@ -29,6 +29,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Banana
  */
@@ -142,7 +143,7 @@ public class Banana {
 
     // add `lengthCm` to the URL query string
     if (getLengthCm() != null) {
-      joiner.add(String.format("%slengthCm%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getLengthCm()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%slengthCm%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getLengthCm()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/BananaReq.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/BananaReq.java
index 4a789a29f5..a963fd4df1 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/BananaReq.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/BananaReq.java
@@ -29,6 +29,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * BananaReq
  */
@@ -173,12 +174,12 @@ public class BananaReq {
 
     // add `lengthCm` to the URL query string
     if (getLengthCm() != null) {
-      joiner.add(String.format("%slengthCm%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getLengthCm()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%slengthCm%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getLengthCm()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `sweet` to the URL query string
     if (getSweet() != null) {
-      joiner.add(String.format("%ssweet%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getSweet()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%ssweet%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getSweet()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/BasquePig.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/BasquePig.java
index 828bff2d1e..d1fea74004 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/BasquePig.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/BasquePig.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * BasquePig
  */
@@ -141,7 +142,7 @@ public class BasquePig {
 
     // add `className` to the URL query string
     if (getClassName() != null) {
-      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Capitalization.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Capitalization.java
index 1eb4fb85c6..0c9584cd5c 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Capitalization.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Capitalization.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Capitalization
  */
@@ -296,32 +297,32 @@ public class Capitalization {
 
     // add `smallCamel` to the URL query string
     if (getSmallCamel() != null) {
-      joiner.add(String.format("%ssmallCamel%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getSmallCamel()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%ssmallCamel%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getSmallCamel()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `CapitalCamel` to the URL query string
     if (getCapitalCamel() != null) {
-      joiner.add(String.format("%sCapitalCamel%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getCapitalCamel()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sCapitalCamel%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getCapitalCamel()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `small_Snake` to the URL query string
     if (getSmallSnake() != null) {
-      joiner.add(String.format("%ssmall_Snake%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getSmallSnake()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%ssmall_Snake%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getSmallSnake()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `Capital_Snake` to the URL query string
     if (getCapitalSnake() != null) {
-      joiner.add(String.format("%sCapital_Snake%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getCapitalSnake()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sCapital_Snake%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getCapitalSnake()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `SCA_ETH_Flow_Points` to the URL query string
     if (getScAETHFlowPoints() != null) {
-      joiner.add(String.format("%sSCA_ETH_Flow_Points%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getScAETHFlowPoints()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sSCA_ETH_Flow_Points%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getScAETHFlowPoints()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `ATT_NAME` to the URL query string
     if (getATTNAME() != null) {
-      joiner.add(String.format("%sATT_NAME%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getATTNAME()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sATT_NAME%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getATTNAME()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Cat.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Cat.java
index 7737df6212..87882ac9e6 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Cat.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Cat.java
@@ -34,6 +34,7 @@ import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
 import org.openapitools.client.JSON;
+import org.openapitools.client.ApiClient;
 /**
  * Cat
  */
@@ -167,17 +168,17 @@ public class Cat extends Animal {
 
     // add `className` to the URL query string
     if (getClassName() != null) {
-      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `color` to the URL query string
     if (getColor() != null) {
-      joiner.add(String.format("%scolor%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getColor()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%scolor%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getColor()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `declawed` to the URL query string
     if (getDeclawed() != null) {
-      joiner.add(String.format("%sdeclawed%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getDeclawed()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sdeclawed%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getDeclawed()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Category.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Category.java
index 7562153c62..1fa8481a8c 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Category.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Category.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Category
  */
@@ -172,12 +173,12 @@ public class Category {
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ChildCat.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ChildCat.java
index bf73aa294b..4c58be5abc 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ChildCat.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ChildCat.java
@@ -35,6 +35,7 @@ import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
 import org.openapitools.client.JSON;
+import org.openapitools.client.ApiClient;
 /**
  * ChildCat
  */
@@ -199,12 +200,12 @@ public class ChildCat extends ParentPet {
 
     // add `pet_type` to the URL query string
     if (getPetType() != null) {
-      joiner.add(String.format("%spet_type%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPetType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%spet_type%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPetType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ClassModel.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ClassModel.java
index 39f6846bdb..1bed990abe 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ClassModel.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ClassModel.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Model for testing model with \&quot;_class\&quot; property
  */
@@ -141,7 +142,7 @@ public class ClassModel {
 
     // add `_class` to the URL query string
     if (getPropertyClass() != null) {
-      joiner.add(String.format("%s_class%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPropertyClass()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%s_class%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPropertyClass()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Client.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Client.java
index d0ea797c99..2423467a34 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Client.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Client.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Client
  */
@@ -141,7 +142,7 @@ public class Client {
 
     // add `client` to the URL query string
     if (getClient() != null) {
-      joiner.add(String.format("%sclient%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getClient()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sclient%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getClient()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ComplexQuadrilateral.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ComplexQuadrilateral.java
index f998086a23..95ffa9905e 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ComplexQuadrilateral.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ComplexQuadrilateral.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * ComplexQuadrilateral
  */
@@ -172,12 +173,12 @@ public class ComplexQuadrilateral {
 
     // add `shapeType` to the URL query string
     if (getShapeType() != null) {
-      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `quadrilateralType` to the URL query string
     if (getQuadrilateralType() != null) {
-      joiner.add(String.format("%squadrilateralType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getQuadrilateralType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%squadrilateralType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getQuadrilateralType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/DanishPig.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/DanishPig.java
index 6e14eee038..bb5694874a 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/DanishPig.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/DanishPig.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * DanishPig
  */
@@ -141,7 +142,7 @@ public class DanishPig {
 
     // add `className` to the URL query string
     if (getClassName() != null) {
-      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/DeprecatedObject.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/DeprecatedObject.java
index acc59dccec..ed552fda57 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/DeprecatedObject.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/DeprecatedObject.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * DeprecatedObject
  * @deprecated
@@ -143,7 +144,7 @@ public class DeprecatedObject {
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Dog.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Dog.java
index 0bc201b0bb..89879e50c4 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Dog.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Dog.java
@@ -33,6 +33,7 @@ import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
 import org.openapitools.client.JSON;
+import org.openapitools.client.ApiClient;
 /**
  * Dog
  */
@@ -166,17 +167,17 @@ public class Dog extends Animal {
 
     // add `className` to the URL query string
     if (getClassName() != null) {
-      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `color` to the URL query string
     if (getColor() != null) {
-      joiner.add(String.format("%scolor%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getColor()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%scolor%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getColor()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `breed` to the URL query string
     if (getBreed() != null) {
-      joiner.add(String.format("%sbreed%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getBreed()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sbreed%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getBreed()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Drawing.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Drawing.java
index 2a777636eb..f91f60b96f 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Drawing.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Drawing.java
@@ -44,6 +44,7 @@ import java.util.NoSuchElementException;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Drawing
  */
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/EnumArrays.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/EnumArrays.java
index 3e8063d219..c1ecf705a9 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/EnumArrays.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/EnumArrays.java
@@ -30,6 +30,7 @@ import java.util.List;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * EnumArrays
  */
@@ -252,7 +253,7 @@ public class EnumArrays {
 
     // add `just_symbol` to the URL query string
     if (getJustSymbol() != null) {
-      joiner.add(String.format("%sjust_symbol%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getJustSymbol()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sjust_symbol%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getJustSymbol()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `array_enum` to the URL query string
@@ -260,7 +261,7 @@ public class EnumArrays {
       for (int i = 0; i < getArrayEnum().size(); i++) {
         joiner.add(String.format("%sarray_enum%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getArrayEnum().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getArrayEnum().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/EnumTest.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/EnumTest.java
index 114d60091c..00f7564e53 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/EnumTest.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/EnumTest.java
@@ -36,6 +36,7 @@ import java.util.NoSuchElementException;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * EnumTest
  */
@@ -595,47 +596,47 @@ public class EnumTest {
 
     // add `enum_string` to the URL query string
     if (getEnumString() != null) {
-      joiner.add(String.format("%senum_string%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getEnumString()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%senum_string%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getEnumString()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `enum_string_required` to the URL query string
     if (getEnumStringRequired() != null) {
-      joiner.add(String.format("%senum_string_required%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getEnumStringRequired()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%senum_string_required%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getEnumStringRequired()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `enum_integer` to the URL query string
     if (getEnumInteger() != null) {
-      joiner.add(String.format("%senum_integer%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getEnumInteger()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%senum_integer%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getEnumInteger()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `enum_integer_only` to the URL query string
     if (getEnumIntegerOnly() != null) {
-      joiner.add(String.format("%senum_integer_only%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getEnumIntegerOnly()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%senum_integer_only%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getEnumIntegerOnly()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `enum_number` to the URL query string
     if (getEnumNumber() != null) {
-      joiner.add(String.format("%senum_number%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getEnumNumber()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%senum_number%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getEnumNumber()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `outerEnum` to the URL query string
     if (getOuterEnum() != null) {
-      joiner.add(String.format("%souterEnum%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getOuterEnum()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%souterEnum%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getOuterEnum()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `outerEnumInteger` to the URL query string
     if (getOuterEnumInteger() != null) {
-      joiner.add(String.format("%souterEnumInteger%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getOuterEnumInteger()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%souterEnumInteger%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getOuterEnumInteger()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `outerEnumDefaultValue` to the URL query string
     if (getOuterEnumDefaultValue() != null) {
-      joiner.add(String.format("%souterEnumDefaultValue%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getOuterEnumDefaultValue()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%souterEnumDefaultValue%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getOuterEnumDefaultValue()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `outerEnumIntegerDefaultValue` to the URL query string
     if (getOuterEnumIntegerDefaultValue() != null) {
-      joiner.add(String.format("%souterEnumIntegerDefaultValue%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getOuterEnumIntegerDefaultValue()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%souterEnumIntegerDefaultValue%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getOuterEnumIntegerDefaultValue()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/EquilateralTriangle.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/EquilateralTriangle.java
index d137ea91f6..5ee54360fa 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/EquilateralTriangle.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/EquilateralTriangle.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * EquilateralTriangle
  */
@@ -172,12 +173,12 @@ public class EquilateralTriangle {
 
     // add `shapeType` to the URL query string
     if (getShapeType() != null) {
-      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `triangleType` to the URL query string
     if (getTriangleType() != null) {
-      joiner.add(String.format("%striangleType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getTriangleType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%striangleType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getTriangleType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/FakeBigDecimalMap200Response.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/FakeBigDecimalMap200Response.java
index 332d62fc70..0c54f2550b 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/FakeBigDecimalMap200Response.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/FakeBigDecimalMap200Response.java
@@ -31,6 +31,7 @@ import java.util.Map;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * FakeBigDecimalMap200Response
  */
@@ -183,7 +184,7 @@ public class FakeBigDecimalMap200Response {
 
     // add `someId` to the URL query string
     if (getSomeId() != null) {
-      joiner.add(String.format("%ssomeId%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getSomeId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%ssomeId%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getSomeId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `someMap` to the URL query string
@@ -191,7 +192,7 @@ public class FakeBigDecimalMap200Response {
       for (String _key : getSomeMap().keySet()) {
         joiner.add(String.format("%ssomeMap%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getSomeMap().get(_key), URLEncoder.encode(String.valueOf(getSomeMap().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getSomeMap().get(_key), URLEncoder.encode(ApiClient.valueToString(getSomeMap().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/FileSchemaTestClass.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/FileSchemaTestClass.java
index 3d29813f2c..04e7ddad69 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/FileSchemaTestClass.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/FileSchemaTestClass.java
@@ -31,6 +31,7 @@ import org.openapitools.client.model.ModelFile;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * FileSchemaTestClass
  */
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Foo.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Foo.java
index 2b9d97c46f..8404e0c51b 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Foo.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Foo.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Foo
  */
@@ -141,7 +142,7 @@ public class Foo {
 
     // add `bar` to the URL query string
     if (getBar() != null) {
-      joiner.add(String.format("%sbar%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getBar()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sbar%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getBar()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/FooGetDefaultResponse.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/FooGetDefaultResponse.java
index a4677da364..a457967c58 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/FooGetDefaultResponse.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/FooGetDefaultResponse.java
@@ -29,6 +29,7 @@ import org.openapitools.client.model.Foo;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * FooGetDefaultResponse
  */
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/FormatTest.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/FormatTest.java
index 9e85c2962f..3774c4fe71 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/FormatTest.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/FormatTest.java
@@ -33,6 +33,7 @@ import java.util.UUID;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * FormatTest
  */
@@ -621,82 +622,82 @@ public class FormatTest {
 
     // add `integer` to the URL query string
     if (getInteger() != null) {
-      joiner.add(String.format("%sinteger%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getInteger()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sinteger%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getInteger()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `int32` to the URL query string
     if (getInt32() != null) {
-      joiner.add(String.format("%sint32%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getInt32()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sint32%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getInt32()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `int64` to the URL query string
     if (getInt64() != null) {
-      joiner.add(String.format("%sint64%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getInt64()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sint64%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getInt64()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `number` to the URL query string
     if (getNumber() != null) {
-      joiner.add(String.format("%snumber%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getNumber()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%snumber%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getNumber()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `float` to the URL query string
     if (getFloat() != null) {
-      joiner.add(String.format("%sfloat%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getFloat()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sfloat%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getFloat()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `double` to the URL query string
     if (getDouble() != null) {
-      joiner.add(String.format("%sdouble%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getDouble()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sdouble%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getDouble()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `decimal` to the URL query string
     if (getDecimal() != null) {
-      joiner.add(String.format("%sdecimal%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getDecimal()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sdecimal%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getDecimal()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `string` to the URL query string
     if (getString() != null) {
-      joiner.add(String.format("%sstring%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getString()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sstring%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getString()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `byte` to the URL query string
     if (getByte() != null) {
-      joiner.add(String.format("%sbyte%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getByte()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sbyte%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getByte()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `binary` to the URL query string
     if (getBinary() != null) {
-      joiner.add(String.format("%sbinary%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getBinary()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sbinary%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getBinary()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `date` to the URL query string
     if (getDate() != null) {
-      joiner.add(String.format("%sdate%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getDate()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sdate%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getDate()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `dateTime` to the URL query string
     if (getDateTime() != null) {
-      joiner.add(String.format("%sdateTime%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getDateTime()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sdateTime%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getDateTime()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `uuid` to the URL query string
     if (getUuid() != null) {
-      joiner.add(String.format("%suuid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getUuid()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%suuid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getUuid()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `password` to the URL query string
     if (getPassword() != null) {
-      joiner.add(String.format("%spassword%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPassword()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%spassword%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPassword()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `pattern_with_digits` to the URL query string
     if (getPatternWithDigits() != null) {
-      joiner.add(String.format("%spattern_with_digits%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPatternWithDigits()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%spattern_with_digits%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPatternWithDigits()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `pattern_with_digits_and_delimiter` to the URL query string
     if (getPatternWithDigitsAndDelimiter() != null) {
-      joiner.add(String.format("%spattern_with_digits_and_delimiter%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPatternWithDigitsAndDelimiter()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%spattern_with_digits_and_delimiter%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPatternWithDigitsAndDelimiter()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/GrandparentAnimal.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/GrandparentAnimal.java
index fcd3c608a2..77b2c1aca2 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/GrandparentAnimal.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/GrandparentAnimal.java
@@ -32,6 +32,7 @@ import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
 import org.openapitools.client.JSON;
+import org.openapitools.client.ApiClient;
 /**
  * GrandparentAnimal
  */
@@ -155,7 +156,7 @@ public class GrandparentAnimal {
 
     // add `pet_type` to the URL query string
     if (getPetType() != null) {
-      joiner.add(String.format("%spet_type%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPetType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%spet_type%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPetType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/HasOnlyReadOnly.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/HasOnlyReadOnly.java
index e00ee07cdf..c297606be7 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/HasOnlyReadOnly.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/HasOnlyReadOnly.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * HasOnlyReadOnly
  */
@@ -162,12 +163,12 @@ public class HasOnlyReadOnly {
 
     // add `bar` to the URL query string
     if (getBar() != null) {
-      joiner.add(String.format("%sbar%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getBar()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sbar%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getBar()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `foo` to the URL query string
     if (getFoo() != null) {
-      joiner.add(String.format("%sfoo%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getFoo()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sfoo%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getFoo()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/HealthCheckResult.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/HealthCheckResult.java
index fa357a9df0..7ee718a461 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/HealthCheckResult.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/HealthCheckResult.java
@@ -32,6 +32,7 @@ import java.util.NoSuchElementException;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Just a string to inform instance is up and running. Make it nullable in hope to get it as pointer in generated model.
  */
@@ -164,7 +165,7 @@ public class HealthCheckResult {
 
     // add `NullableMessage` to the URL query string
     if (getNullableMessage() != null) {
-      joiner.add(String.format("%sNullableMessage%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getNullableMessage()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sNullableMessage%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getNullableMessage()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/IsoscelesTriangle.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/IsoscelesTriangle.java
index 95a46c400d..be0d552579 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/IsoscelesTriangle.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/IsoscelesTriangle.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * IsoscelesTriangle
  */
@@ -172,12 +173,12 @@ public class IsoscelesTriangle {
 
     // add `shapeType` to the URL query string
     if (getShapeType() != null) {
-      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `triangleType` to the URL query string
     if (getTriangleType() != null) {
-      joiner.add(String.format("%striangleType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getTriangleType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%striangleType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getTriangleType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/MapTest.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/MapTest.java
index 26318d30f3..a904f8483e 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/MapTest.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/MapTest.java
@@ -30,6 +30,7 @@ import java.util.Map;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * MapTest
  */
@@ -306,7 +307,7 @@ public class MapTest {
       for (String _key : getMapMapOfString().keySet()) {
         joiner.add(String.format("%smap_map_of_string%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getMapMapOfString().get(_key), URLEncoder.encode(String.valueOf(getMapMapOfString().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getMapMapOfString().get(_key), URLEncoder.encode(ApiClient.valueToString(getMapMapOfString().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -315,7 +316,7 @@ public class MapTest {
       for (String _key : getMapOfEnumString().keySet()) {
         joiner.add(String.format("%smap_of_enum_string%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getMapOfEnumString().get(_key), URLEncoder.encode(String.valueOf(getMapOfEnumString().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getMapOfEnumString().get(_key), URLEncoder.encode(ApiClient.valueToString(getMapOfEnumString().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -324,7 +325,7 @@ public class MapTest {
       for (String _key : getDirectMap().keySet()) {
         joiner.add(String.format("%sdirect_map%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getDirectMap().get(_key), URLEncoder.encode(String.valueOf(getDirectMap().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getDirectMap().get(_key), URLEncoder.encode(ApiClient.valueToString(getDirectMap().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -333,7 +334,7 @@ public class MapTest {
       for (String _key : getIndirectMap().keySet()) {
         joiner.add(String.format("%sindirect_map%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getIndirectMap().get(_key), URLEncoder.encode(String.valueOf(getIndirectMap().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getIndirectMap().get(_key), URLEncoder.encode(ApiClient.valueToString(getIndirectMap().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/MixedPropertiesAndAdditionalPropertiesClass.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/MixedPropertiesAndAdditionalPropertiesClass.java
index 9c9b33daf7..9c15bbf1bd 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/MixedPropertiesAndAdditionalPropertiesClass.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/MixedPropertiesAndAdditionalPropertiesClass.java
@@ -33,6 +33,7 @@ import org.openapitools.client.model.Animal;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * MixedPropertiesAndAdditionalPropertiesClass
  */
@@ -216,12 +217,12 @@ public class MixedPropertiesAndAdditionalPropertiesClass {
 
     // add `uuid` to the URL query string
     if (getUuid() != null) {
-      joiner.add(String.format("%suuid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getUuid()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%suuid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getUuid()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `dateTime` to the URL query string
     if (getDateTime() != null) {
-      joiner.add(String.format("%sdateTime%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getDateTime()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sdateTime%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getDateTime()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `map` to the URL query string
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Model200Response.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Model200Response.java
index fa368a161e..b1a7744705 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Model200Response.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Model200Response.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Model for testing model name starting with number
  */
@@ -172,12 +173,12 @@ public class Model200Response {
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `class` to the URL query string
     if (getPropertyClass() != null) {
-      joiner.add(String.format("%sclass%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPropertyClass()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sclass%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPropertyClass()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ModelApiResponse.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ModelApiResponse.java
index f90d056d7e..1a553b9866 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ModelApiResponse.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ModelApiResponse.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * ModelApiResponse
  */
@@ -203,17 +204,17 @@ public class ModelApiResponse {
 
     // add `code` to the URL query string
     if (getCode() != null) {
-      joiner.add(String.format("%scode%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getCode()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%scode%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getCode()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `type` to the URL query string
     if (getType() != null) {
-      joiner.add(String.format("%stype%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%stype%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `message` to the URL query string
     if (getMessage() != null) {
-      joiner.add(String.format("%smessage%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getMessage()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%smessage%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getMessage()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ModelFile.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ModelFile.java
index 3552bf166d..9df68eab30 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ModelFile.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ModelFile.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Must be named &#x60;File&#x60; for test.
  */
@@ -141,7 +142,7 @@ public class ModelFile {
 
     // add `sourceURI` to the URL query string
     if (getSourceURI() != null) {
-      joiner.add(String.format("%ssourceURI%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getSourceURI()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%ssourceURI%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getSourceURI()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ModelList.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ModelList.java
index 8ad456ce03..8a375e98ff 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ModelList.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ModelList.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * ModelList
  */
@@ -141,7 +142,7 @@ public class ModelList {
 
     // add `123-list` to the URL query string
     if (get123list() != null) {
-      joiner.add(String.format("%s123-list%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(get123list()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%s123-list%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(get123list()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ModelReturn.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ModelReturn.java
index eb94f20ae4..42e7e42017 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ModelReturn.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ModelReturn.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Model for testing reserved words
  */
@@ -141,7 +142,7 @@ public class ModelReturn {
 
     // add `return` to the URL query string
     if (getReturn() != null) {
-      joiner.add(String.format("%sreturn%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getReturn()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sreturn%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getReturn()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Name.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Name.java
index 66bb7c973f..da3a59b01b 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Name.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Name.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Model for testing model name same as property name
  */
@@ -224,22 +225,22 @@ public class Name {
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `snake_case` to the URL query string
     if (getSnakeCase() != null) {
-      joiner.add(String.format("%ssnake_case%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getSnakeCase()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%ssnake_case%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getSnakeCase()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `property` to the URL query string
     if (getProperty() != null) {
-      joiner.add(String.format("%sproperty%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getProperty()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sproperty%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getProperty()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `123Number` to the URL query string
     if (get123number() != null) {
-      joiner.add(String.format("%s123Number%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(get123number()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%s123Number%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(get123number()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/NullableClass.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/NullableClass.java
index 4ca88cd215..a568d2b48a 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/NullableClass.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/NullableClass.java
@@ -43,6 +43,7 @@ import java.util.NoSuchElementException;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * NullableClass
  */
@@ -699,32 +700,32 @@ public class NullableClass extends HashMap<String, Object> {
 
     // add `integer_prop` to the URL query string
     if (getIntegerProp() != null) {
-      joiner.add(String.format("%sinteger_prop%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getIntegerProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sinteger_prop%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getIntegerProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `number_prop` to the URL query string
     if (getNumberProp() != null) {
-      joiner.add(String.format("%snumber_prop%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getNumberProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%snumber_prop%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getNumberProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `boolean_prop` to the URL query string
     if (getBooleanProp() != null) {
-      joiner.add(String.format("%sboolean_prop%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getBooleanProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sboolean_prop%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getBooleanProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `string_prop` to the URL query string
     if (getStringProp() != null) {
-      joiner.add(String.format("%sstring_prop%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getStringProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sstring_prop%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getStringProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `date_prop` to the URL query string
     if (getDateProp() != null) {
-      joiner.add(String.format("%sdate_prop%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getDateProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sdate_prop%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getDateProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `datetime_prop` to the URL query string
     if (getDatetimeProp() != null) {
-      joiner.add(String.format("%sdatetime_prop%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getDatetimeProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sdatetime_prop%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getDatetimeProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `array_nullable_prop` to the URL query string
@@ -732,7 +733,7 @@ public class NullableClass extends HashMap<String, Object> {
       for (int i = 0; i < getArrayNullableProp().size(); i++) {
         joiner.add(String.format("%sarray_nullable_prop%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getArrayNullableProp().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getArrayNullableProp().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -741,7 +742,7 @@ public class NullableClass extends HashMap<String, Object> {
       for (int i = 0; i < getArrayAndItemsNullableProp().size(); i++) {
         joiner.add(String.format("%sarray_and_items_nullable_prop%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getArrayAndItemsNullableProp().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getArrayAndItemsNullableProp().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -750,7 +751,7 @@ public class NullableClass extends HashMap<String, Object> {
       for (int i = 0; i < getArrayItemsNullable().size(); i++) {
         joiner.add(String.format("%sarray_items_nullable%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getArrayItemsNullable().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getArrayItemsNullable().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -759,7 +760,7 @@ public class NullableClass extends HashMap<String, Object> {
       for (String _key : getObjectNullableProp().keySet()) {
         joiner.add(String.format("%sobject_nullable_prop%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getObjectNullableProp().get(_key), URLEncoder.encode(String.valueOf(getObjectNullableProp().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getObjectNullableProp().get(_key), URLEncoder.encode(ApiClient.valueToString(getObjectNullableProp().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -768,7 +769,7 @@ public class NullableClass extends HashMap<String, Object> {
       for (String _key : getObjectAndItemsNullableProp().keySet()) {
         joiner.add(String.format("%sobject_and_items_nullable_prop%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getObjectAndItemsNullableProp().get(_key), URLEncoder.encode(String.valueOf(getObjectAndItemsNullableProp().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getObjectAndItemsNullableProp().get(_key), URLEncoder.encode(ApiClient.valueToString(getObjectAndItemsNullableProp().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -777,7 +778,7 @@ public class NullableClass extends HashMap<String, Object> {
       for (String _key : getObjectItemsNullable().keySet()) {
         joiner.add(String.format("%sobject_items_nullable%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, _key, containerSuffix),
-            getObjectItemsNullable().get(_key), URLEncoder.encode(String.valueOf(getObjectItemsNullable().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            getObjectItemsNullable().get(_key), URLEncoder.encode(ApiClient.valueToString(getObjectItemsNullable().get(_key)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/NumberOnly.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/NumberOnly.java
index a23aca1189..121fb9b74c 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/NumberOnly.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/NumberOnly.java
@@ -29,6 +29,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * NumberOnly
  */
@@ -142,7 +143,7 @@ public class NumberOnly {
 
     // add `JustNumber` to the URL query string
     if (getJustNumber() != null) {
-      joiner.add(String.format("%sJustNumber%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getJustNumber()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sJustNumber%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getJustNumber()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ObjectWithDeprecatedFields.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ObjectWithDeprecatedFields.java
index dc6837b6ba..06c7298c78 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ObjectWithDeprecatedFields.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ObjectWithDeprecatedFields.java
@@ -32,6 +32,7 @@ import org.openapitools.client.model.DeprecatedObject;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * ObjectWithDeprecatedFields
  */
@@ -252,12 +253,12 @@ public class ObjectWithDeprecatedFields {
 
     // add `uuid` to the URL query string
     if (getUuid() != null) {
-      joiner.add(String.format("%suuid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getUuid()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%suuid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getUuid()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `deprecatedRef` to the URL query string
@@ -270,7 +271,7 @@ public class ObjectWithDeprecatedFields {
       for (int i = 0; i < getBars().size(); i++) {
         joiner.add(String.format("%sbars%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getBars().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getBars().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Order.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Order.java
index 153709ed75..152d9fd203 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Order.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Order.java
@@ -29,6 +29,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Order
  */
@@ -334,32 +335,32 @@ public class Order {
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `petId` to the URL query string
     if (getPetId() != null) {
-      joiner.add(String.format("%spetId%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPetId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%spetId%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPetId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `quantity` to the URL query string
     if (getQuantity() != null) {
-      joiner.add(String.format("%squantity%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getQuantity()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%squantity%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getQuantity()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `shipDate` to the URL query string
     if (getShipDate() != null) {
-      joiner.add(String.format("%sshipDate%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getShipDate()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sshipDate%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getShipDate()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `status` to the URL query string
     if (getStatus() != null) {
-      joiner.add(String.format("%sstatus%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getStatus()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sstatus%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getStatus()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `complete` to the URL query string
     if (getComplete() != null) {
-      joiner.add(String.format("%scomplete%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getComplete()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%scomplete%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getComplete()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/OuterComposite.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/OuterComposite.java
index fb75e1d579..c78c4e813e 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/OuterComposite.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/OuterComposite.java
@@ -29,6 +29,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * OuterComposite
  */
@@ -204,17 +205,17 @@ public class OuterComposite {
 
     // add `my_number` to the URL query string
     if (getMyNumber() != null) {
-      joiner.add(String.format("%smy_number%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getMyNumber()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%smy_number%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getMyNumber()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `my_string` to the URL query string
     if (getMyString() != null) {
-      joiner.add(String.format("%smy_string%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getMyString()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%smy_string%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getMyString()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `my_boolean` to the URL query string
     if (getMyBoolean() != null) {
-      joiner.add(String.format("%smy_boolean%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getMyBoolean()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%smy_boolean%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getMyBoolean()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ParentPet.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ParentPet.java
index bf73ee44f4..7559e93638 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ParentPet.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ParentPet.java
@@ -33,6 +33,7 @@ import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
 import org.openapitools.client.JSON;
+import org.openapitools.client.ApiClient;
 /**
  * ParentPet
  */
@@ -131,7 +132,7 @@ public class ParentPet extends GrandparentAnimal {
 
     // add `pet_type` to the URL query string
     if (getPetType() != null) {
-      joiner.add(String.format("%spet_type%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPetType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%spet_type%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPetType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Pet.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Pet.java
index d22e451e0e..0393f5f4de 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Pet.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Pet.java
@@ -32,6 +32,7 @@ import org.openapitools.client.model.Tag;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Pet
  */
@@ -353,7 +354,7 @@ public class Pet {
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `category` to the URL query string
@@ -363,7 +364,7 @@ public class Pet {
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `photoUrls` to the URL query string
@@ -371,7 +372,7 @@ public class Pet {
       for (int i = 0; i < getPhotoUrls().size(); i++) {
         joiner.add(String.format("%sphotoUrls%s%s=%s", prefix, suffix,
             "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix),
-            URLEncoder.encode(String.valueOf(getPhotoUrls().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+            URLEncoder.encode(ApiClient.valueToString(getPhotoUrls().get(i)), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
       }
     }
 
@@ -387,7 +388,7 @@ public class Pet {
 
     // add `status` to the URL query string
     if (getStatus() != null) {
-      joiner.add(String.format("%sstatus%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getStatus()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sstatus%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getStatus()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/QuadrilateralInterface.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/QuadrilateralInterface.java
index 0348810a0c..bd03d5cd6f 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/QuadrilateralInterface.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/QuadrilateralInterface.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * QuadrilateralInterface
  */
@@ -141,7 +142,7 @@ public class QuadrilateralInterface {
 
     // add `quadrilateralType` to the URL query string
     if (getQuadrilateralType() != null) {
-      joiner.add(String.format("%squadrilateralType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getQuadrilateralType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%squadrilateralType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getQuadrilateralType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ReadOnlyFirst.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ReadOnlyFirst.java
index 9f4b479974..dc5ff8182c 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ReadOnlyFirst.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ReadOnlyFirst.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * ReadOnlyFirst
  */
@@ -170,12 +171,12 @@ public class ReadOnlyFirst {
 
     // add `bar` to the URL query string
     if (getBar() != null) {
-      joiner.add(String.format("%sbar%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getBar()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sbar%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getBar()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `baz` to the URL query string
     if (getBaz() != null) {
-      joiner.add(String.format("%sbaz%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getBaz()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sbaz%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getBaz()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ScaleneTriangle.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ScaleneTriangle.java
index 2b030ebf3d..28d1f933f6 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ScaleneTriangle.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ScaleneTriangle.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * ScaleneTriangle
  */
@@ -172,12 +173,12 @@ public class ScaleneTriangle {
 
     // add `shapeType` to the URL query string
     if (getShapeType() != null) {
-      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `triangleType` to the URL query string
     if (getTriangleType() != null) {
-      joiner.add(String.format("%striangleType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getTriangleType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%striangleType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getTriangleType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ShapeInterface.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ShapeInterface.java
index 2efaf5cab5..afab07f765 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ShapeInterface.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/ShapeInterface.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * ShapeInterface
  */
@@ -141,7 +142,7 @@ public class ShapeInterface {
 
     // add `shapeType` to the URL query string
     if (getShapeType() != null) {
-      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/SimpleQuadrilateral.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/SimpleQuadrilateral.java
index aa70bcc23e..9d08a07b09 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/SimpleQuadrilateral.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/SimpleQuadrilateral.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * SimpleQuadrilateral
  */
@@ -172,12 +173,12 @@ public class SimpleQuadrilateral {
 
     // add `shapeType` to the URL query string
     if (getShapeType() != null) {
-      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sshapeType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getShapeType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `quadrilateralType` to the URL query string
     if (getQuadrilateralType() != null) {
-      joiner.add(String.format("%squadrilateralType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getQuadrilateralType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%squadrilateralType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getQuadrilateralType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/SpecialModelName.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/SpecialModelName.java
index 1e355ae482..c0bbda3f89 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/SpecialModelName.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/SpecialModelName.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * SpecialModelName
  */
@@ -172,12 +173,12 @@ public class SpecialModelName {
 
     // add `$special[property.name]` to the URL query string
     if (get$SpecialPropertyName() != null) {
-      joiner.add(String.format("%s$special[property.name]%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(get$SpecialPropertyName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%s$special[property.name]%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(get$SpecialPropertyName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `_special_model.name_` to the URL query string
     if (getSpecialModelName() != null) {
-      joiner.add(String.format("%s_special_model.name_%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getSpecialModelName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%s_special_model.name_%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getSpecialModelName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Tag.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Tag.java
index 0b52eddf79..fce946808a 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Tag.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Tag.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Tag
  */
@@ -172,12 +173,12 @@ public class Tag {
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `name` to the URL query string
     if (getName() != null) {
-      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sname%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/TestInlineFreeformAdditionalPropertiesRequest.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/TestInlineFreeformAdditionalPropertiesRequest.java
index 9783a28394..bbd7e8f66f 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/TestInlineFreeformAdditionalPropertiesRequest.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/TestInlineFreeformAdditionalPropertiesRequest.java
@@ -34,6 +34,7 @@ import java.util.Map;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * TestInlineFreeformAdditionalPropertiesRequest
  */
@@ -194,7 +195,7 @@ public class TestInlineFreeformAdditionalPropertiesRequest extends HashMap<Strin
 
     // add `someProperty` to the URL query string
     if (getSomeProperty() != null) {
-      joiner.add(String.format("%ssomeProperty%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getSomeProperty()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%ssomeProperty%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getSomeProperty()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/TriangleInterface.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/TriangleInterface.java
index 74d50df609..dd6e21843a 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/TriangleInterface.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/TriangleInterface.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * TriangleInterface
  */
@@ -141,7 +142,7 @@ public class TriangleInterface {
 
     // add `triangleType` to the URL query string
     if (getTriangleType() != null) {
-      joiner.add(String.format("%striangleType%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getTriangleType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%striangleType%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getTriangleType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/User.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/User.java
index d83a787a9f..c7d197baa7 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/User.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/User.java
@@ -32,6 +32,7 @@ import java.util.NoSuchElementException;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * User
  */
@@ -521,62 +522,62 @@ public class User {
 
     // add `id` to the URL query string
     if (getId() != null) {
-      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sid%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getId()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `username` to the URL query string
     if (getUsername() != null) {
-      joiner.add(String.format("%susername%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getUsername()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%susername%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getUsername()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `firstName` to the URL query string
     if (getFirstName() != null) {
-      joiner.add(String.format("%sfirstName%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getFirstName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sfirstName%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getFirstName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `lastName` to the URL query string
     if (getLastName() != null) {
-      joiner.add(String.format("%slastName%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getLastName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%slastName%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getLastName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `email` to the URL query string
     if (getEmail() != null) {
-      joiner.add(String.format("%semail%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getEmail()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%semail%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getEmail()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `password` to the URL query string
     if (getPassword() != null) {
-      joiner.add(String.format("%spassword%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPassword()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%spassword%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPassword()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `phone` to the URL query string
     if (getPhone() != null) {
-      joiner.add(String.format("%sphone%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getPhone()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sphone%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getPhone()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `userStatus` to the URL query string
     if (getUserStatus() != null) {
-      joiner.add(String.format("%suserStatus%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getUserStatus()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%suserStatus%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getUserStatus()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `objectWithNoDeclaredProps` to the URL query string
     if (getObjectWithNoDeclaredProps() != null) {
-      joiner.add(String.format("%sobjectWithNoDeclaredProps%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getObjectWithNoDeclaredProps()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sobjectWithNoDeclaredProps%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getObjectWithNoDeclaredProps()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `objectWithNoDeclaredPropsNullable` to the URL query string
     if (getObjectWithNoDeclaredPropsNullable() != null) {
-      joiner.add(String.format("%sobjectWithNoDeclaredPropsNullable%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getObjectWithNoDeclaredPropsNullable()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sobjectWithNoDeclaredPropsNullable%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getObjectWithNoDeclaredPropsNullable()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `anyTypeProp` to the URL query string
     if (getAnyTypeProp() != null) {
-      joiner.add(String.format("%sanyTypeProp%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getAnyTypeProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sanyTypeProp%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getAnyTypeProp()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `anyTypePropNullable` to the URL query string
     if (getAnyTypePropNullable() != null) {
-      joiner.add(String.format("%sanyTypePropNullable%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getAnyTypePropNullable()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sanyTypePropNullable%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getAnyTypePropNullable()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Whale.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Whale.java
index 77b2c3c51e..540bc70d53 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Whale.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Whale.java
@@ -28,6 +28,7 @@ import java.util.Arrays;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Whale
  */
@@ -203,17 +204,17 @@ public class Whale {
 
     // add `hasBaleen` to the URL query string
     if (getHasBaleen() != null) {
-      joiner.add(String.format("%shasBaleen%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getHasBaleen()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%shasBaleen%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getHasBaleen()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `hasTeeth` to the URL query string
     if (getHasTeeth() != null) {
-      joiner.add(String.format("%shasTeeth%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getHasTeeth()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%shasTeeth%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getHasTeeth()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `className` to the URL query string
     if (getClassName() != null) {
-      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Zebra.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Zebra.java
index 40b913b395..28d7f2abb0 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Zebra.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/model/Zebra.java
@@ -34,6 +34,7 @@ import java.util.Map;
 import com.fasterxml.jackson.annotation.JsonPropertyOrder;
 
 
+import org.openapitools.client.ApiClient;
 /**
  * Zebra
  */
@@ -262,12 +263,12 @@ public class Zebra extends HashMap<String, Object> {
 
     // add `type` to the URL query string
     if (getType() != null) {
-      joiner.add(String.format("%stype%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%stype%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getType()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     // add `className` to the URL query string
     if (getClassName() != null) {
-      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(String.valueOf(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
+      joiner.add(String.format("%sclassName%s=%s", prefix, suffix, URLEncoder.encode(ApiClient.valueToString(getClassName()), StandardCharsets.UTF_8).replaceAll("\\+", "%20")));
     }
 
     return joiner.toString();