diff --git a/pom.xml b/pom.xml
index a47757a359..ce92a4dd8e 100644
--- a/pom.xml
+++ b/pom.xml
@@ -438,6 +438,7 @@
                 <module>samples/client/petstore/android/default</module>
                 <module>samples/client/petstore/clojure</module>
                 <module>samples/client/petstore/java/default</module>
+                <module>samples/client/petstore/java/feign</module>
                 <module>samples/client/petstore/java/jersey2</module>
                 <module>samples/client/petstore/java/okhttp-gson</module>
                 <module>samples/client/petstore/java/retrofit</module>
diff --git a/samples/client/petstore/java/default/src/test/java/io/swagger/TestUtils.java b/samples/client/petstore/java/default/src/test/java/io/swagger/TestUtils.java
new file mode 100644
index 0000000000..7ddf142426
--- /dev/null
+++ b/samples/client/petstore/java/default/src/test/java/io/swagger/TestUtils.java
@@ -0,0 +1,17 @@
+package io.swagger;
+
+import java.util.Random;
+import java.util.concurrent.atomic.AtomicLong;
+
+public class TestUtils {
+    private static final AtomicLong atomicId = createAtomicId();
+
+    public static long nextId() {
+      return atomicId.getAndIncrement();
+    }
+
+    private static AtomicLong createAtomicId() {
+        int baseId = new Random(System.currentTimeMillis()).nextInt(1000000) + 20000;
+        return new AtomicLong((long) baseId);
+    }
+}
diff --git a/samples/client/petstore/java/default/src/test/java/io/swagger/petstore/test/PetApiTest.java b/samples/client/petstore/java/default/src/test/java/io/swagger/petstore/test/PetApiTest.java
index c0bee9328d..c678923186 100644
--- a/samples/client/petstore/java/default/src/test/java/io/swagger/petstore/test/PetApiTest.java
+++ b/samples/client/petstore/java/default/src/test/java/io/swagger/petstore/test/PetApiTest.java
@@ -1,9 +1,8 @@
 package io.swagger.petstore.test;
 
-import io.swagger.client.ApiClient;
-import io.swagger.client.ApiException;
-import io.swagger.client.Configuration;
+import io.swagger.TestUtils;
 
+import io.swagger.client.*;
 import io.swagger.client.api.*;
 import io.swagger.client.auth.*;
 import io.swagger.client.model.*;
@@ -203,7 +202,7 @@ public class PetApiTest {
 
     private Pet createRandomPet() {
         Pet pet = new Pet();
-        pet.setId(System.currentTimeMillis());
+        pet.setId(TestUtils.nextId());
         pet.setName("gorilla");
 
         Category category = new Category();
diff --git a/samples/client/petstore/java/default/src/test/java/io/swagger/petstore/test/StoreApiTest.java b/samples/client/petstore/java/default/src/test/java/io/swagger/petstore/test/StoreApiTest.java
index 6094f2242e..8ba6caec77 100644
--- a/samples/client/petstore/java/default/src/test/java/io/swagger/petstore/test/StoreApiTest.java
+++ b/samples/client/petstore/java/default/src/test/java/io/swagger/petstore/test/StoreApiTest.java
@@ -1,5 +1,7 @@
 package io.swagger.petstore.test;
 
+import io.swagger.TestUtils;
+
 import io.swagger.client.ApiException;
 
 import io.swagger.client.*;
@@ -63,7 +65,7 @@ public class StoreApiTest {
 
     private Order createOrder() {
         Order order = new Order();
-        order.setId(new Long(System.currentTimeMillis()));
+        order.setId(TestUtils.nextId());
         order.setPetId(new Long(200));
         order.setQuantity(new Integer(13));
         order.setShipDate(new java.util.Date());
diff --git a/samples/client/petstore/java/default/src/test/java/io/swagger/petstore/test/UserApiTest.java b/samples/client/petstore/java/default/src/test/java/io/swagger/petstore/test/UserApiTest.java
index a3f257f568..7e3fd23644 100644
--- a/samples/client/petstore/java/default/src/test/java/io/swagger/petstore/test/UserApiTest.java
+++ b/samples/client/petstore/java/default/src/test/java/io/swagger/petstore/test/UserApiTest.java
@@ -1,5 +1,7 @@
 package io.swagger.petstore.test;
 
+import io.swagger.TestUtils;
+
 import io.swagger.client.api.*;
 import io.swagger.client.auth.*;
 import io.swagger.client.model.*;
@@ -72,7 +74,7 @@ public class UserApiTest {
 
     private User createUser() {
         User user = new User();
-        user.setId(System.currentTimeMillis());
+        user.setId(TestUtils.nextId());
         user.setUsername("fred" + user.getId());
         user.setFirstName("Fred");
         user.setLastName("Meyer");
diff --git a/samples/client/petstore/java/feign/hello.txt b/samples/client/petstore/java/feign/hello.txt
new file mode 100644
index 0000000000..6769dd60bd
--- /dev/null
+++ b/samples/client/petstore/java/feign/hello.txt
@@ -0,0 +1 @@
+Hello world!
\ No newline at end of file
diff --git a/samples/client/petstore/java/feign/src/test/java/io/swagger/TestUtils.java b/samples/client/petstore/java/feign/src/test/java/io/swagger/TestUtils.java
new file mode 100644
index 0000000000..7ddf142426
--- /dev/null
+++ b/samples/client/petstore/java/feign/src/test/java/io/swagger/TestUtils.java
@@ -0,0 +1,17 @@
+package io.swagger;
+
+import java.util.Random;
+import java.util.concurrent.atomic.AtomicLong;
+
+public class TestUtils {
+    private static final AtomicLong atomicId = createAtomicId();
+
+    public static long nextId() {
+      return atomicId.getAndIncrement();
+    }
+
+    private static AtomicLong createAtomicId() {
+        int baseId = new Random(System.currentTimeMillis()).nextInt(1000000) + 20000;
+        return new AtomicLong((long) baseId);
+    }
+}
diff --git a/samples/client/petstore/java/feign/src/test/java/io/swagger/petstore/test/PetApiTest.java b/samples/client/petstore/java/feign/src/test/java/io/swagger/petstore/test/PetApiTest.java
index aef8ab2561..bf06865290 100644
--- a/samples/client/petstore/java/feign/src/test/java/io/swagger/petstore/test/PetApiTest.java
+++ b/samples/client/petstore/java/feign/src/test/java/io/swagger/petstore/test/PetApiTest.java
@@ -1,7 +1,8 @@
 package io.swagger.petstore.test;
 
-import io.swagger.client.ApiClient;
+import io.swagger.TestUtils;
 
+import io.swagger.client.ApiClient;
 import io.swagger.client.api.*;
 import io.swagger.client.model.*;
 
@@ -183,7 +184,7 @@ public class PetApiTest {
 
     private Pet createRandomPet() {
         Pet pet = new Pet();
-        pet.setId(System.currentTimeMillis());
+        pet.setId(TestUtils.nextId());
         pet.setName("gorilla");
 
         Category category = new Category();
diff --git a/samples/client/petstore/java/feign/src/test/java/io/swagger/petstore/test/StoreApiTest.java b/samples/client/petstore/java/feign/src/test/java/io/swagger/petstore/test/StoreApiTest.java
index dd5bf4e71f..b9aaabb511 100644
--- a/samples/client/petstore/java/feign/src/test/java/io/swagger/petstore/test/StoreApiTest.java
+++ b/samples/client/petstore/java/feign/src/test/java/io/swagger/petstore/test/StoreApiTest.java
@@ -1,5 +1,9 @@
 package io.swagger.petstore.test;
 
+import feign.FeignException;
+
+import io.swagger.TestUtils;
+
 import io.swagger.client.*;
 import io.swagger.client.api.*;
 import io.swagger.client.model.*;
@@ -44,15 +48,19 @@ public class StoreApiTest {
         Order fetched = api.getOrderById(order.getId().toString());
         assertEquals(fetched.getId(), order.getId());
 
-        api.deleteOrder(String.valueOf(order.getId()));
+        api.deleteOrder(order.getId().toString());
 
-        api.getOrderById(order.getId().toString());
-//        fail("expected an error");
+        try {
+            api.getOrderById(order.getId().toString());
+            fail("expected an error");
+        } catch (FeignException e) {
+            assertTrue(e.getMessage().startsWith("status 404 "));
+        }
     }
 
     private Order createOrder() {
         Order order = new Order();
-        order.setId(new Long(System.currentTimeMillis()));
+        order.setId(TestUtils.nextId());
         order.setPetId(new Long(200));
         order.setQuantity(new Integer(13));
         order.setShipDate(new java.util.Date());
diff --git a/samples/client/petstore/java/feign/src/test/java/io/swagger/petstore/test/UserApiTest.java b/samples/client/petstore/java/feign/src/test/java/io/swagger/petstore/test/UserApiTest.java
index 1615dbf1dc..d5d10b39d7 100644
--- a/samples/client/petstore/java/feign/src/test/java/io/swagger/petstore/test/UserApiTest.java
+++ b/samples/client/petstore/java/feign/src/test/java/io/swagger/petstore/test/UserApiTest.java
@@ -1,5 +1,7 @@
 package io.swagger.petstore.test;
 
+import io.swagger.TestUtils;
+
 import io.swagger.client.ApiClient;
 import io.swagger.client.api.*;
 import io.swagger.client.model.*;
@@ -73,7 +75,7 @@ public class UserApiTest {
 
     private User createUser() {
         User user = new User();
-        user.setId(System.currentTimeMillis());
+        user.setId(TestUtils.nextId());
         user.setUsername("fred" + user.getId());
         user.setFirstName("Fred");
         user.setLastName("Meyer");
diff --git a/samples/client/petstore/java/jersey2/src/test/java/io/swagger/TestUtils.java b/samples/client/petstore/java/jersey2/src/test/java/io/swagger/TestUtils.java
new file mode 100644
index 0000000000..7ddf142426
--- /dev/null
+++ b/samples/client/petstore/java/jersey2/src/test/java/io/swagger/TestUtils.java
@@ -0,0 +1,17 @@
+package io.swagger;
+
+import java.util.Random;
+import java.util.concurrent.atomic.AtomicLong;
+
+public class TestUtils {
+    private static final AtomicLong atomicId = createAtomicId();
+
+    public static long nextId() {
+      return atomicId.getAndIncrement();
+    }
+
+    private static AtomicLong createAtomicId() {
+        int baseId = new Random(System.currentTimeMillis()).nextInt(1000000) + 20000;
+        return new AtomicLong((long) baseId);
+    }
+}
diff --git a/samples/client/petstore/java/jersey2/src/test/java/io/swagger/petstore/test/PetApiTest.java b/samples/client/petstore/java/jersey2/src/test/java/io/swagger/petstore/test/PetApiTest.java
index c0bee9328d..c678923186 100644
--- a/samples/client/petstore/java/jersey2/src/test/java/io/swagger/petstore/test/PetApiTest.java
+++ b/samples/client/petstore/java/jersey2/src/test/java/io/swagger/petstore/test/PetApiTest.java
@@ -1,9 +1,8 @@
 package io.swagger.petstore.test;
 
-import io.swagger.client.ApiClient;
-import io.swagger.client.ApiException;
-import io.swagger.client.Configuration;
+import io.swagger.TestUtils;
 
+import io.swagger.client.*;
 import io.swagger.client.api.*;
 import io.swagger.client.auth.*;
 import io.swagger.client.model.*;
@@ -203,7 +202,7 @@ public class PetApiTest {
 
     private Pet createRandomPet() {
         Pet pet = new Pet();
-        pet.setId(System.currentTimeMillis());
+        pet.setId(TestUtils.nextId());
         pet.setName("gorilla");
 
         Category category = new Category();
diff --git a/samples/client/petstore/java/jersey2/src/test/java/io/swagger/petstore/test/StoreApiTest.java b/samples/client/petstore/java/jersey2/src/test/java/io/swagger/petstore/test/StoreApiTest.java
index 6094f2242e..58072ea75f 100644
--- a/samples/client/petstore/java/jersey2/src/test/java/io/swagger/petstore/test/StoreApiTest.java
+++ b/samples/client/petstore/java/jersey2/src/test/java/io/swagger/petstore/test/StoreApiTest.java
@@ -1,6 +1,6 @@
 package io.swagger.petstore.test;
 
-import io.swagger.client.ApiException;
+import io.swagger.TestUtils;
 
 import io.swagger.client.*;
 import io.swagger.client.api.*;
@@ -63,7 +63,7 @@ public class StoreApiTest {
 
     private Order createOrder() {
         Order order = new Order();
-        order.setId(new Long(System.currentTimeMillis()));
+        order.setId(TestUtils.nextId());
         order.setPetId(new Long(200));
         order.setQuantity(new Integer(13));
         order.setShipDate(new java.util.Date());
diff --git a/samples/client/petstore/java/jersey2/src/test/java/io/swagger/petstore/test/UserApiTest.java b/samples/client/petstore/java/jersey2/src/test/java/io/swagger/petstore/test/UserApiTest.java
index a3f257f568..7e3fd23644 100644
--- a/samples/client/petstore/java/jersey2/src/test/java/io/swagger/petstore/test/UserApiTest.java
+++ b/samples/client/petstore/java/jersey2/src/test/java/io/swagger/petstore/test/UserApiTest.java
@@ -1,5 +1,7 @@
 package io.swagger.petstore.test;
 
+import io.swagger.TestUtils;
+
 import io.swagger.client.api.*;
 import io.swagger.client.auth.*;
 import io.swagger.client.model.*;
@@ -72,7 +74,7 @@ public class UserApiTest {
 
     private User createUser() {
         User user = new User();
-        user.setId(System.currentTimeMillis());
+        user.setId(TestUtils.nextId());
         user.setUsername("fred" + user.getId());
         user.setFirstName("Fred");
         user.setLastName("Meyer");
diff --git a/samples/client/petstore/java/okhttp-gson/src/test/java/io/swagger/TestUtils.java b/samples/client/petstore/java/okhttp-gson/src/test/java/io/swagger/TestUtils.java
new file mode 100644
index 0000000000..7ddf142426
--- /dev/null
+++ b/samples/client/petstore/java/okhttp-gson/src/test/java/io/swagger/TestUtils.java
@@ -0,0 +1,17 @@
+package io.swagger;
+
+import java.util.Random;
+import java.util.concurrent.atomic.AtomicLong;
+
+public class TestUtils {
+    private static final AtomicLong atomicId = createAtomicId();
+
+    public static long nextId() {
+      return atomicId.getAndIncrement();
+    }
+
+    private static AtomicLong createAtomicId() {
+        int baseId = new Random(System.currentTimeMillis()).nextInt(1000000) + 20000;
+        return new AtomicLong((long) baseId);
+    }
+}
diff --git a/samples/client/petstore/java/okhttp-gson/src/test/java/io/swagger/petstore/test/PetApiTest.java b/samples/client/petstore/java/okhttp-gson/src/test/java/io/swagger/petstore/test/PetApiTest.java
index 56cc807398..e65de7791a 100644
--- a/samples/client/petstore/java/okhttp-gson/src/test/java/io/swagger/petstore/test/PetApiTest.java
+++ b/samples/client/petstore/java/okhttp-gson/src/test/java/io/swagger/petstore/test/PetApiTest.java
@@ -1,5 +1,7 @@
 package io.swagger.petstore.test;
 
+import io.swagger.TestUtils;
+
 import io.swagger.client.*;
 import io.swagger.client.api.*;
 import io.swagger.client.auth.*;
@@ -312,7 +314,7 @@ public class PetApiTest {
 
     private Pet createRandomPet() {
         Pet pet = new Pet();
-        pet.setId(System.currentTimeMillis());
+        pet.setId(TestUtils.nextId());
         pet.setName("gorilla");
 
         Category category = new Category();
diff --git a/samples/client/petstore/java/okhttp-gson/src/test/java/io/swagger/petstore/test/StoreApiTest.java b/samples/client/petstore/java/okhttp-gson/src/test/java/io/swagger/petstore/test/StoreApiTest.java
index 589dae1a3c..d62bfaf175 100644
--- a/samples/client/petstore/java/okhttp-gson/src/test/java/io/swagger/petstore/test/StoreApiTest.java
+++ b/samples/client/petstore/java/okhttp-gson/src/test/java/io/swagger/petstore/test/StoreApiTest.java
@@ -1,5 +1,6 @@
 package io.swagger.petstore.test;
 
+import io.swagger.TestUtils;
 import io.swagger.client.ApiException;
 
 import io.swagger.client.*;
@@ -67,7 +68,7 @@ public class StoreApiTest {
 
     private Order createOrder() {
         Order order = new Order();
-        order.setId(new Long(System.currentTimeMillis()));
+        order.setId(TestUtils.nextId());
         order.setPetId(new Long(200));
         order.setQuantity(new Integer(13));
         order.setShipDate(new java.util.Date());
diff --git a/samples/client/petstore/java/okhttp-gson/src/test/java/io/swagger/petstore/test/UserApiTest.java b/samples/client/petstore/java/okhttp-gson/src/test/java/io/swagger/petstore/test/UserApiTest.java
index a3f257f568..7e3fd23644 100644
--- a/samples/client/petstore/java/okhttp-gson/src/test/java/io/swagger/petstore/test/UserApiTest.java
+++ b/samples/client/petstore/java/okhttp-gson/src/test/java/io/swagger/petstore/test/UserApiTest.java
@@ -1,5 +1,7 @@
 package io.swagger.petstore.test;
 
+import io.swagger.TestUtils;
+
 import io.swagger.client.api.*;
 import io.swagger.client.auth.*;
 import io.swagger.client.model.*;
@@ -72,7 +74,7 @@ public class UserApiTest {
 
     private User createUser() {
         User user = new User();
-        user.setId(System.currentTimeMillis());
+        user.setId(TestUtils.nextId());
         user.setUsername("fred" + user.getId());
         user.setFirstName("Fred");
         user.setLastName("Meyer");
diff --git a/samples/client/petstore/java/retrofit/hello.txt b/samples/client/petstore/java/retrofit/hello.txt
new file mode 100644
index 0000000000..6769dd60bd
--- /dev/null
+++ b/samples/client/petstore/java/retrofit/hello.txt
@@ -0,0 +1 @@
+Hello world!
\ No newline at end of file
diff --git a/samples/client/petstore/java/retrofit/src/test/java/io/swagger/TestUtils.java b/samples/client/petstore/java/retrofit/src/test/java/io/swagger/TestUtils.java
new file mode 100644
index 0000000000..7ddf142426
--- /dev/null
+++ b/samples/client/petstore/java/retrofit/src/test/java/io/swagger/TestUtils.java
@@ -0,0 +1,17 @@
+package io.swagger;
+
+import java.util.Random;
+import java.util.concurrent.atomic.AtomicLong;
+
+public class TestUtils {
+    private static final AtomicLong atomicId = createAtomicId();
+
+    public static long nextId() {
+      return atomicId.getAndIncrement();
+    }
+
+    private static AtomicLong createAtomicId() {
+        int baseId = new Random(System.currentTimeMillis()).nextInt(1000000) + 20000;
+        return new AtomicLong((long) baseId);
+    }
+}
diff --git a/samples/client/petstore/java/retrofit/src/test/java/io/swagger/petstore/test/PetApiTest.java b/samples/client/petstore/java/retrofit/src/test/java/io/swagger/petstore/test/PetApiTest.java
index 1ff1dbb10e..a943a8ffe6 100644
--- a/samples/client/petstore/java/retrofit/src/test/java/io/swagger/petstore/test/PetApiTest.java
+++ b/samples/client/petstore/java/retrofit/src/test/java/io/swagger/petstore/test/PetApiTest.java
@@ -1,5 +1,7 @@
 package io.swagger.petstore.test;
 
+import io.swagger.TestUtils;
+
 import io.swagger.client.ApiClient;
 import io.swagger.client.api.*;
 import io.swagger.client.model.*;
@@ -172,7 +174,7 @@ public class PetApiTest {
 
     private Pet createRandomPet() {
         Pet pet = new Pet();
-        pet.setId(System.currentTimeMillis());
+        pet.setId(TestUtils.nextId());
         pet.setName("gorilla");
 
         Category category = new Category();
@@ -185,4 +187,4 @@ public class PetApiTest {
 
         return pet;
     }
-}
\ No newline at end of file
+}
diff --git a/samples/client/petstore/java/retrofit/src/test/java/io/swagger/petstore/test/StoreApiTest.java b/samples/client/petstore/java/retrofit/src/test/java/io/swagger/petstore/test/StoreApiTest.java
index 95079f71af..3e0574c887 100644
--- a/samples/client/petstore/java/retrofit/src/test/java/io/swagger/petstore/test/StoreApiTest.java
+++ b/samples/client/petstore/java/retrofit/src/test/java/io/swagger/petstore/test/StoreApiTest.java
@@ -1,5 +1,7 @@
 package io.swagger.petstore.test;
 
+import io.swagger.TestUtils;
+
 import io.swagger.client.ApiClient;
 import io.swagger.client.api.*;
 import io.swagger.client.model.*;
@@ -56,7 +58,7 @@ public class StoreApiTest {
 
     private Order createOrder() {
         Order order = new Order();
-        order.setId(new Long(System.currentTimeMillis()));
+        order.setId(new Long(TestUtils.nextId()));
         order.setPetId(new Long(200));
         order.setQuantity(new Integer(13));
         order.setShipDate(new java.util.Date());
@@ -65,4 +67,4 @@ public class StoreApiTest {
 
         return order;
     }
-}
\ No newline at end of file
+}
diff --git a/samples/client/petstore/java/retrofit/src/test/java/io/swagger/petstore/test/UserApiTest.java b/samples/client/petstore/java/retrofit/src/test/java/io/swagger/petstore/test/UserApiTest.java
index f99d7f513c..97ef057e37 100644
--- a/samples/client/petstore/java/retrofit/src/test/java/io/swagger/petstore/test/UserApiTest.java
+++ b/samples/client/petstore/java/retrofit/src/test/java/io/swagger/petstore/test/UserApiTest.java
@@ -1,5 +1,7 @@
 package io.swagger.petstore.test;
 
+import io.swagger.TestUtils;
+
 import io.swagger.client.ApiClient;
 import io.swagger.client.api.*;
 import io.swagger.client.model.*;
@@ -70,7 +72,7 @@ public class UserApiTest {
 
     private User createUser() {
         User user = new User();
-        user.setId(System.currentTimeMillis());
+        user.setId(TestUtils.nextId());
         user.setUsername("fred" + user.getId());
         user.setFirstName("Fred");
         user.setLastName("Meyer");
@@ -81,4 +83,4 @@ public class UserApiTest {
 
         return user;
     }
-}
\ No newline at end of file
+}
diff --git a/samples/client/petstore/java/retrofit2/hello.txt b/samples/client/petstore/java/retrofit2/hello.txt
new file mode 100644
index 0000000000..6769dd60bd
--- /dev/null
+++ b/samples/client/petstore/java/retrofit2/hello.txt
@@ -0,0 +1 @@
+Hello world!
\ No newline at end of file
diff --git a/samples/client/petstore/java/retrofit2/src/test/java/io/swagger/TestUtils.java b/samples/client/petstore/java/retrofit2/src/test/java/io/swagger/TestUtils.java
new file mode 100644
index 0000000000..7ddf142426
--- /dev/null
+++ b/samples/client/petstore/java/retrofit2/src/test/java/io/swagger/TestUtils.java
@@ -0,0 +1,17 @@
+package io.swagger;
+
+import java.util.Random;
+import java.util.concurrent.atomic.AtomicLong;
+
+public class TestUtils {
+    private static final AtomicLong atomicId = createAtomicId();
+
+    public static long nextId() {
+      return atomicId.getAndIncrement();
+    }
+
+    private static AtomicLong createAtomicId() {
+        int baseId = new Random(System.currentTimeMillis()).nextInt(1000000) + 20000;
+        return new AtomicLong((long) baseId);
+    }
+}
diff --git a/samples/client/petstore/java/retrofit2/src/test/java/io/swagger/petstore/test/PetApiTest.java b/samples/client/petstore/java/retrofit2/src/test/java/io/swagger/petstore/test/PetApiTest.java
index 8506fc08f5..ec5116e45f 100644
--- a/samples/client/petstore/java/retrofit2/src/test/java/io/swagger/petstore/test/PetApiTest.java
+++ b/samples/client/petstore/java/retrofit2/src/test/java/io/swagger/petstore/test/PetApiTest.java
@@ -1,5 +1,7 @@
 package io.swagger.petstore.test;
 
+import io.swagger.TestUtils;
+
 import io.swagger.client.ApiClient;
 import io.swagger.client.api.*;
 import io.swagger.client.model.*;
@@ -32,7 +34,7 @@ public class PetApiTest {
     public void testCreateAndGetPet() throws Exception {
         Pet pet = createRandomPet();
         Response<Void> rp2 = api.addPet(pet).execute();
-        
+
         Response<Pet> rp = api.getPetById(pet.getId()).execute();
         Pet fetched = rp.body();
         assertNotNull(fetched);
@@ -171,7 +173,7 @@ public class PetApiTest {
 
     private Pet createRandomPet() {
         Pet pet = new Pet();
-        pet.setId(System.currentTimeMillis());
+        pet.setId(TestUtils.nextId());
         pet.setName("gorilla");
 
         Category category = new Category();
@@ -184,4 +186,4 @@ public class PetApiTest {
 
         return pet;
     }
-}
\ No newline at end of file
+}
diff --git a/samples/client/petstore/java/retrofit2/src/test/java/io/swagger/petstore/test/StoreApiTest.java b/samples/client/petstore/java/retrofit2/src/test/java/io/swagger/petstore/test/StoreApiTest.java
index 786b070870..71f77ec9b4 100644
--- a/samples/client/petstore/java/retrofit2/src/test/java/io/swagger/petstore/test/StoreApiTest.java
+++ b/samples/client/petstore/java/retrofit2/src/test/java/io/swagger/petstore/test/StoreApiTest.java
@@ -1,5 +1,7 @@
 package io.swagger.petstore.test;
 
+import io.swagger.TestUtils;
+
 import io.swagger.client.ApiClient;
 import io.swagger.client.api.*;
 import io.swagger.client.model.*;
@@ -47,12 +49,12 @@ public class StoreApiTest {
         api.deleteOrder(String.valueOf(order.getId())).execute();
 
         api.getOrderById(String.valueOf(order.getId())).execute();
-        //also in retrofit 1 should return an error but don't, check server api impl.       
+        //also in retrofit 1 should return an error but don't, check server api impl.
     }
 
     private Order createOrder() {
         Order order = new Order();
-        order.setId(new Long(System.currentTimeMillis()));
+        order.setId(new Long(TestUtils.nextId()));
         order.setPetId(new Long(200));
         order.setQuantity(new Integer(13));
         order.setShipDate(new java.util.Date());
@@ -61,4 +63,4 @@ public class StoreApiTest {
 
         return order;
     }
-}
\ No newline at end of file
+}
diff --git a/samples/client/petstore/java/retrofit2/src/test/java/io/swagger/petstore/test/UserApiTest.java b/samples/client/petstore/java/retrofit2/src/test/java/io/swagger/petstore/test/UserApiTest.java
index d496144c9f..fbcdc483da 100644
--- a/samples/client/petstore/java/retrofit2/src/test/java/io/swagger/petstore/test/UserApiTest.java
+++ b/samples/client/petstore/java/retrofit2/src/test/java/io/swagger/petstore/test/UserApiTest.java
@@ -1,5 +1,7 @@
 package io.swagger.petstore.test;
 
+import io.swagger.TestUtils;
+
 import io.swagger.client.ApiClient;
 import io.swagger.client.api.*;
 import io.swagger.client.model.*;
@@ -70,7 +72,7 @@ public class UserApiTest {
 
     private User createUser() {
         User user = new User();
-        user.setId(System.currentTimeMillis());
+        user.setId(TestUtils.nextId());
         user.setUsername("fred");
         user.setFirstName("Fred");
         user.setLastName("Meyer");
@@ -81,4 +83,4 @@ public class UserApiTest {
 
         return user;
     }
-}
\ No newline at end of file
+}