diff --git a/modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/play24/Play24CallFactory.mustache b/modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/play24/Play24CallFactory.mustache
index 62df91f7983..6e83afd045c 100644
--- a/modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/play24/Play24CallFactory.mustache
+++ b/modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/play24/Play24CallFactory.mustache
@@ -16,6 +16,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 
 /**
  * Creates {@link Call} instances that invoke underlying {@link WSClient}
@@ -163,20 +164,23 @@ public class Play24CallFactory implements okhttp3.Call.Factory {
 
                        @Override
                        public MediaType contentType() {
-                           return MediaType.parse(r.getHeader("Content-Type"));
+                           return Optional.ofNullable(r.getHeader("Content-Type"))
+                                          .map(MediaType::parse)
+                                          .orElse(null);
                        }
 
                        @Override
                        public long contentLength() {
-                           return r.getBody().getBytes().length;
+                           return r.asByteArray().length;
                        }
 
                        @Override
                        public BufferedSource source() {
-                           return new Buffer().write(r.getBody().getBytes());
+                           return new Buffer().write(r.asByteArray());
                        }
+                       
                    });
-
+                   
             for (Map.Entry<String, List<String>> entry : r.getAllHeaders().entrySet()) {
                 for (String value : entry.getValue()) {
                     builder.addHeader(entry.getKey(), value);
diff --git a/modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/play25/Play25CallFactory.mustache b/modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/play25/Play25CallFactory.mustache
index 152c9023f69..516f67b8a2b 100644
--- a/modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/play25/Play25CallFactory.mustache
+++ b/modules/swagger-codegen/src/main/resources/Java/libraries/retrofit2/play25/Play25CallFactory.mustache
@@ -15,6 +15,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.concurrent.CompletionStage;
 
 /**
@@ -160,20 +161,23 @@ public class Play25CallFactory implements okhttp3.Call.Factory {
 
                        @Override
                        public MediaType contentType() {
-                           return MediaType.parse(r.getHeader("Content-Type"));
+                           return Optional.ofNullable(r.getHeader("Content-Type"))
+                                          .map(MediaType::parse)
+                                          .orElse(null);
                        }
 
                        @Override
                        public long contentLength() {
-                           return r.getBody().getBytes().length;
+                           return r.asByteArray().length;
                        }
 
                        @Override
                        public BufferedSource source() {
-                           return new Buffer().write(r.getBody().getBytes());
+                           return new Buffer().write(r.asByteArray());
                        }
+                       
                    });
-
+                   
             for (Map.Entry<String, List<String>> entry : r.getAllHeaders().entrySet()) {
                 for (String value : entry.getValue()) {
                     builder.addHeader(entry.getKey(), value);
diff --git a/samples/client/petstore/java/retrofit2-play24/src/main/java/io/swagger/client/Play24CallFactory.java b/samples/client/petstore/java/retrofit2-play24/src/main/java/io/swagger/client/Play24CallFactory.java
index 64e2278ad98..43a53e52dd4 100644
--- a/samples/client/petstore/java/retrofit2-play24/src/main/java/io/swagger/client/Play24CallFactory.java
+++ b/samples/client/petstore/java/retrofit2-play24/src/main/java/io/swagger/client/Play24CallFactory.java
@@ -16,6 +16,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 
 /**
  * Creates {@link Call} instances that invoke underlying {@link WSClient}
@@ -163,20 +164,23 @@ public class Play24CallFactory implements okhttp3.Call.Factory {
 
                        @Override
                        public MediaType contentType() {
-                           return MediaType.parse(r.getHeader("Content-Type"));
+                           return Optional.ofNullable(r.getHeader("Content-Type"))
+                                          .map(MediaType::parse)
+                                          .orElse(null);
                        }
 
                        @Override
                        public long contentLength() {
-                           return r.getBody().getBytes().length;
+                           return r.asByteArray().length;
                        }
 
                        @Override
                        public BufferedSource source() {
-                           return new Buffer().write(r.getBody().getBytes());
+                           return new Buffer().write(r.asByteArray());
                        }
+                       
                    });
-
+                   
             for (Map.Entry<String, List<String>> entry : r.getAllHeaders().entrySet()) {
                 for (String value : entry.getValue()) {
                     builder.addHeader(entry.getKey(), value);
diff --git a/samples/client/petstore/java/retrofit2-play25/src/main/java/io/swagger/client/Play25CallFactory.java b/samples/client/petstore/java/retrofit2-play25/src/main/java/io/swagger/client/Play25CallFactory.java
index f5c6f21fa0b..48bef1a6d6d 100644
--- a/samples/client/petstore/java/retrofit2-play25/src/main/java/io/swagger/client/Play25CallFactory.java
+++ b/samples/client/petstore/java/retrofit2-play25/src/main/java/io/swagger/client/Play25CallFactory.java
@@ -15,6 +15,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.concurrent.CompletionStage;
 
 /**
@@ -160,20 +161,23 @@ public class Play25CallFactory implements okhttp3.Call.Factory {
 
                        @Override
                        public MediaType contentType() {
-                           return MediaType.parse(r.getHeader("Content-Type"));
+                           return Optional.ofNullable(r.getHeader("Content-Type"))
+                                          .map(MediaType::parse)
+                                          .orElse(null);
                        }
 
                        @Override
                        public long contentLength() {
-                           return r.getBody().getBytes().length;
+                           return r.asByteArray().length;
                        }
 
                        @Override
                        public BufferedSource source() {
-                           return new Buffer().write(r.getBody().getBytes());
+                           return new Buffer().write(r.asByteArray());
                        }
+                       
                    });
-
+                   
             for (Map.Entry<String, List<String>> entry : r.getAllHeaders().entrySet()) {
                 for (String value : entry.getValue()) {
                     builder.addHeader(entry.getKey(), value);
diff --git a/samples/client/petstore/java/retrofit2/src/main/java/io/swagger/client/api/FakeApi.java b/samples/client/petstore/java/retrofit2/src/main/java/io/swagger/client/api/FakeApi.java
index 70293f5985b..d169b8111b7 100644
--- a/samples/client/petstore/java/retrofit2/src/main/java/io/swagger/client/api/FakeApi.java
+++ b/samples/client/petstore/java/retrofit2/src/main/java/io/swagger/client/api/FakeApi.java
@@ -6,6 +6,7 @@ import retrofit2.Call;
 import retrofit2.http.*;
 
 import okhttp3.RequestBody;
+import okhttp3.ResponseBody;
 
 import java.math.BigDecimal;
 import io.swagger.client.model.Client;
diff --git a/samples/client/petstore/java/retrofit2/src/main/java/io/swagger/client/api/FakeClassnameTags123Api.java b/samples/client/petstore/java/retrofit2/src/main/java/io/swagger/client/api/FakeClassnameTags123Api.java
index 8435dbc4cd6..c31c31c9233 100644
--- a/samples/client/petstore/java/retrofit2/src/main/java/io/swagger/client/api/FakeClassnameTags123Api.java
+++ b/samples/client/petstore/java/retrofit2/src/main/java/io/swagger/client/api/FakeClassnameTags123Api.java
@@ -6,6 +6,7 @@ import retrofit2.Call;
 import retrofit2.http.*;
 
 import okhttp3.RequestBody;
+import okhttp3.ResponseBody;
 
 import io.swagger.client.model.Client;
 
diff --git a/samples/client/petstore/java/retrofit2/src/main/java/io/swagger/client/api/PetApi.java b/samples/client/petstore/java/retrofit2/src/main/java/io/swagger/client/api/PetApi.java
index 06dff092eec..8d48189ce93 100644
--- a/samples/client/petstore/java/retrofit2/src/main/java/io/swagger/client/api/PetApi.java
+++ b/samples/client/petstore/java/retrofit2/src/main/java/io/swagger/client/api/PetApi.java
@@ -6,6 +6,7 @@ import retrofit2.Call;
 import retrofit2.http.*;
 
 import okhttp3.RequestBody;
+import okhttp3.ResponseBody;
 
 import java.io.File;
 import io.swagger.client.model.ModelApiResponse;
diff --git a/samples/client/petstore/java/retrofit2/src/main/java/io/swagger/client/api/StoreApi.java b/samples/client/petstore/java/retrofit2/src/main/java/io/swagger/client/api/StoreApi.java
index 0795776d1fb..99367e1a0c3 100644
--- a/samples/client/petstore/java/retrofit2/src/main/java/io/swagger/client/api/StoreApi.java
+++ b/samples/client/petstore/java/retrofit2/src/main/java/io/swagger/client/api/StoreApi.java
@@ -6,6 +6,7 @@ import retrofit2.Call;
 import retrofit2.http.*;
 
 import okhttp3.RequestBody;
+import okhttp3.ResponseBody;
 
 import io.swagger.client.model.Order;
 
diff --git a/samples/client/petstore/java/retrofit2/src/main/java/io/swagger/client/api/UserApi.java b/samples/client/petstore/java/retrofit2/src/main/java/io/swagger/client/api/UserApi.java
index 8610a28e3a6..ab2074c4e80 100644
--- a/samples/client/petstore/java/retrofit2/src/main/java/io/swagger/client/api/UserApi.java
+++ b/samples/client/petstore/java/retrofit2/src/main/java/io/swagger/client/api/UserApi.java
@@ -6,6 +6,7 @@ import retrofit2.Call;
 import retrofit2.http.*;
 
 import okhttp3.RequestBody;
+import okhttp3.ResponseBody;
 
 import io.swagger.client.model.User;
 
diff --git a/samples/client/petstore/java/retrofit2rx/src/main/java/io/swagger/client/api/FakeApi.java b/samples/client/petstore/java/retrofit2rx/src/main/java/io/swagger/client/api/FakeApi.java
index efcaa38530f..1104aaeced5 100644
--- a/samples/client/petstore/java/retrofit2rx/src/main/java/io/swagger/client/api/FakeApi.java
+++ b/samples/client/petstore/java/retrofit2rx/src/main/java/io/swagger/client/api/FakeApi.java
@@ -6,6 +6,7 @@ import rx.Observable;
 import retrofit2.http.*;
 
 import okhttp3.RequestBody;
+import okhttp3.ResponseBody;
 
 import java.math.BigDecimal;
 import io.swagger.client.model.Client;
diff --git a/samples/client/petstore/java/retrofit2rx/src/main/java/io/swagger/client/api/FakeClassnameTags123Api.java b/samples/client/petstore/java/retrofit2rx/src/main/java/io/swagger/client/api/FakeClassnameTags123Api.java
index a73e3b6d0d8..092f0bf5c50 100644
--- a/samples/client/petstore/java/retrofit2rx/src/main/java/io/swagger/client/api/FakeClassnameTags123Api.java
+++ b/samples/client/petstore/java/retrofit2rx/src/main/java/io/swagger/client/api/FakeClassnameTags123Api.java
@@ -6,6 +6,7 @@ import rx.Observable;
 import retrofit2.http.*;
 
 import okhttp3.RequestBody;
+import okhttp3.ResponseBody;
 
 import io.swagger.client.model.Client;
 
diff --git a/samples/client/petstore/java/retrofit2rx/src/main/java/io/swagger/client/api/PetApi.java b/samples/client/petstore/java/retrofit2rx/src/main/java/io/swagger/client/api/PetApi.java
index 77df46f2546..4f848e7d69f 100644
--- a/samples/client/petstore/java/retrofit2rx/src/main/java/io/swagger/client/api/PetApi.java
+++ b/samples/client/petstore/java/retrofit2rx/src/main/java/io/swagger/client/api/PetApi.java
@@ -6,6 +6,7 @@ import rx.Observable;
 import retrofit2.http.*;
 
 import okhttp3.RequestBody;
+import okhttp3.ResponseBody;
 
 import java.io.File;
 import io.swagger.client.model.ModelApiResponse;
diff --git a/samples/client/petstore/java/retrofit2rx/src/main/java/io/swagger/client/api/StoreApi.java b/samples/client/petstore/java/retrofit2rx/src/main/java/io/swagger/client/api/StoreApi.java
index 5b90fabb23c..b8cbf56d1b3 100644
--- a/samples/client/petstore/java/retrofit2rx/src/main/java/io/swagger/client/api/StoreApi.java
+++ b/samples/client/petstore/java/retrofit2rx/src/main/java/io/swagger/client/api/StoreApi.java
@@ -6,6 +6,7 @@ import rx.Observable;
 import retrofit2.http.*;
 
 import okhttp3.RequestBody;
+import okhttp3.ResponseBody;
 
 import io.swagger.client.model.Order;
 
diff --git a/samples/client/petstore/java/retrofit2rx/src/main/java/io/swagger/client/api/UserApi.java b/samples/client/petstore/java/retrofit2rx/src/main/java/io/swagger/client/api/UserApi.java
index 0d5f22e7224..f0bff0c7730 100644
--- a/samples/client/petstore/java/retrofit2rx/src/main/java/io/swagger/client/api/UserApi.java
+++ b/samples/client/petstore/java/retrofit2rx/src/main/java/io/swagger/client/api/UserApi.java
@@ -6,6 +6,7 @@ import rx.Observable;
 import retrofit2.http.*;
 
 import okhttp3.RequestBody;
+import okhttp3.ResponseBody;
 
 import io.swagger.client.model.User;
 
diff --git a/samples/client/petstore/java/retrofit2rx2/src/main/java/io/swagger/client/api/FakeApi.java b/samples/client/petstore/java/retrofit2rx2/src/main/java/io/swagger/client/api/FakeApi.java
index e78c58d7af7..933e33cb88b 100644
--- a/samples/client/petstore/java/retrofit2rx2/src/main/java/io/swagger/client/api/FakeApi.java
+++ b/samples/client/petstore/java/retrofit2rx2/src/main/java/io/swagger/client/api/FakeApi.java
@@ -6,6 +6,7 @@ import io.reactivex.Observable;
 import retrofit2.http.*;
 
 import okhttp3.RequestBody;
+import okhttp3.ResponseBody;
 
 import java.math.BigDecimal;
 import io.swagger.client.model.Client;
diff --git a/samples/client/petstore/java/retrofit2rx2/src/main/java/io/swagger/client/api/FakeClassnameTags123Api.java b/samples/client/petstore/java/retrofit2rx2/src/main/java/io/swagger/client/api/FakeClassnameTags123Api.java
index 8c46be19331..6e7e3555a21 100644
--- a/samples/client/petstore/java/retrofit2rx2/src/main/java/io/swagger/client/api/FakeClassnameTags123Api.java
+++ b/samples/client/petstore/java/retrofit2rx2/src/main/java/io/swagger/client/api/FakeClassnameTags123Api.java
@@ -6,6 +6,7 @@ import io.reactivex.Observable;
 import retrofit2.http.*;
 
 import okhttp3.RequestBody;
+import okhttp3.ResponseBody;
 
 import io.swagger.client.model.Client;
 
diff --git a/samples/client/petstore/java/retrofit2rx2/src/main/java/io/swagger/client/api/PetApi.java b/samples/client/petstore/java/retrofit2rx2/src/main/java/io/swagger/client/api/PetApi.java
index 4ee45adf41f..e3c9fbf2581 100644
--- a/samples/client/petstore/java/retrofit2rx2/src/main/java/io/swagger/client/api/PetApi.java
+++ b/samples/client/petstore/java/retrofit2rx2/src/main/java/io/swagger/client/api/PetApi.java
@@ -6,6 +6,7 @@ import io.reactivex.Observable;
 import retrofit2.http.*;
 
 import okhttp3.RequestBody;
+import okhttp3.ResponseBody;
 
 import java.io.File;
 import io.swagger.client.model.ModelApiResponse;
diff --git a/samples/client/petstore/java/retrofit2rx2/src/main/java/io/swagger/client/api/StoreApi.java b/samples/client/petstore/java/retrofit2rx2/src/main/java/io/swagger/client/api/StoreApi.java
index 63a378eeae2..746909cce01 100644
--- a/samples/client/petstore/java/retrofit2rx2/src/main/java/io/swagger/client/api/StoreApi.java
+++ b/samples/client/petstore/java/retrofit2rx2/src/main/java/io/swagger/client/api/StoreApi.java
@@ -6,6 +6,7 @@ import io.reactivex.Observable;
 import retrofit2.http.*;
 
 import okhttp3.RequestBody;
+import okhttp3.ResponseBody;
 
 import io.swagger.client.model.Order;
 
diff --git a/samples/client/petstore/java/retrofit2rx2/src/main/java/io/swagger/client/api/UserApi.java b/samples/client/petstore/java/retrofit2rx2/src/main/java/io/swagger/client/api/UserApi.java
index 51e520fccea..1997f4c6cfb 100644
--- a/samples/client/petstore/java/retrofit2rx2/src/main/java/io/swagger/client/api/UserApi.java
+++ b/samples/client/petstore/java/retrofit2rx2/src/main/java/io/swagger/client/api/UserApi.java
@@ -6,6 +6,7 @@ import io.reactivex.Observable;
 import retrofit2.http.*;
 
 import okhttp3.RequestBody;
+import okhttp3.ResponseBody;
 
 import io.swagger.client.model.User;