diff --git a/docs/generators/csharp.md b/docs/generators/csharp.md
index c3b17808dc..102af5dbb0 100644
--- a/docs/generators/csharp.md
+++ b/docs/generators/csharp.md
@@ -88,6 +88,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 <li>List</li>
 <li>Object</li>
 <li>String</li>
+<li>System</li>
 <li>System.IO.Stream</li>
 <li>bool</li>
 <li>bool?</li>
diff --git a/docs/generators/java.md b/docs/generators/java.md
index 941e1c4e2e..db3cb37efc 100644
--- a/docs/generators/java.md
+++ b/docs/generators/java.md
@@ -197,7 +197,9 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 <li>int</li>
 <li>interface</li>
 <li>list</li>
+<li>localdate</li>
 <li>localreturntype</li>
+<li>localtime</li>
 <li>localvaraccept</li>
 <li>localvaraccepts</li>
 <li>localvarauthnames</li>
@@ -215,6 +217,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 <li>new</li>
 <li>null</li>
 <li>object</li>
+<li>offsetdatetime</li>
 <li>package</li>
 <li>private</li>
 <li>protected</li>
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java
index fac8474084..aa8dda7151 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java
@@ -146,7 +146,7 @@ public abstract class AbstractCSharpCodegen extends DefaultCodegen implements Co
                         "foreach", "goto", "if", "implicit", "in", "int", "interface", "internal", "is", "lock",
                         "long", "namespace", "new", "null", "object", "operator", "out", "override", "params",
                         "private", "protected", "public", "readonly", "ref", "return", "sbyte", "sealed",
-                        "short", "sizeof", "stackalloc", "static", "string", "struct", "switch", "this", "throw",
+                        "short", "sizeof", "stackalloc", "static", "string", "struct", "switch", "system", "this", "throw",
                         "true", "try", "typeof", "uint", "ulong", "unchecked", "unsafe", "ushort", "using",
                         "virtual", "void", "volatile", "while")
         );
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java
index 9dae2c164b..fa9a016d1d 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java
@@ -196,7 +196,7 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
                         "import", "public", "throws", "case", "enum", "instanceof", "return", "transient",
                         "catch", "extends", "int", "short", "try", "char", "final", "interface", "static",
                         "void", "class", "finally", "long", "strictfp", "volatile", "const", "float",
-                        "native", "super", "while", "null")
+                        "native", "super", "while", "null", "offsetdatetime", "localdate", "localtime")
         );
 
         languageSpecificPrimitives = Sets.newHashSet("String",