diff --git a/docs/generators/java.md b/docs/generators/java.md
index 1160c36f8b9..4d086325a06 100644
--- a/docs/generators/java.md
+++ b/docs/generators/java.md
@@ -30,6 +30,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |discriminatorCaseSensitive|Whether the discriminator value lookup should be case-sensitive or not. This option only works for Java API client| |true|
 |dynamicOperations|Generate operations dynamically at runtime from an OAS| |false|
 |ensureUniqueParams|Whether to ensure parameter names are unique in an operation (rename parameters that are not).| |true|
+|errorObjectType|Error Object type. (This option is for okhttp-gson-next-gen only)| |null|
 |fullJavaUtil|whether to use fully qualified name for classes under java.util. This option only works for Java API client| |false|
 |gradleProperties|Append additional Gradle proeprties to the gradle.properties file| |null|
 |groupId|groupId in generated pom.xml| |org.openapitools|
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaClientCodegen.java
index 965da6dbd77..f675c9a9c3f 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaClientCodegen.java
@@ -66,6 +66,8 @@ public class JavaClientCodegen extends AbstractJavaCodegen
     public static final String DYNAMIC_OPERATIONS = "dynamicOperations";
     public static final String SUPPORT_STREAMING = "supportStreaming";
     public static final String GRADLE_PROPERTIES= "gradleProperties";
+    public static final String ERROR_OBJECT_TYPE= "errorObjectType";
+    public static final String ERROR_OBJECT_SUBTYPE= "errorObjectSubtype";
 
     public static final String PLAY_24 = "play24";
     public static final String PLAY_25 = "play25";
@@ -118,6 +120,8 @@ public class JavaClientCodegen extends AbstractJavaCodegen
     protected boolean dynamicOperations = false;
     protected boolean supportStreaming = false;
     protected String gradleProperties;
+    protected String errorObjectType;
+    protected List<String> errorObjectSubtype;
     protected String authFolder;
     protected String serializationLibrary = null;
 
@@ -163,6 +167,7 @@ public class JavaClientCodegen extends AbstractJavaCodegen
         cliOptions.add(CliOption.newBoolean(DYNAMIC_OPERATIONS, "Generate operations dynamically at runtime from an OAS", this.dynamicOperations));
         cliOptions.add(CliOption.newBoolean(SUPPORT_STREAMING, "Support streaming endpoint (beta)", this.supportStreaming));
         cliOptions.add(CliOption.newString(GRADLE_PROPERTIES, "Append additional Gradle proeprties to the gradle.properties file"));
+        cliOptions.add(CliOption.newString(ERROR_OBJECT_TYPE, "Error Object type. (This option is for okhttp-gson-next-gen only)"));
         cliOptions.add(CliOption.newString(CONFIG_KEY, "Config key in @RegisterRestClient. Default to none. Only `microprofile` supports this option."));
 
         supportedLibraries.put(JERSEY1, "HTTP client: Jersey client 1.19.x. JSON processing: Jackson 2.9.x. Enable gzip request encoding using '-DuseGzipFeature=true'. IMPORTANT NOTE: jersey 1.x is no longer actively maintained so please upgrade to 'jersey2' or other HTTP libraries instead.");
@@ -343,6 +348,16 @@ public class JavaClientCodegen extends AbstractJavaCodegen
         }
         additionalProperties.put(GRADLE_PROPERTIES, gradleProperties);
 
+        if (additionalProperties.containsKey(ERROR_OBJECT_TYPE)) {
+            this.setErrorObjectType(additionalProperties.get(ERROR_OBJECT_TYPE).toString());
+        }
+        additionalProperties.put(ERROR_OBJECT_TYPE, errorObjectType);
+
+        if (additionalProperties.containsKey(ERROR_OBJECT_SUBTYPE)) {
+            this.setErrorObjectSubtype((List<String>)additionalProperties.get(ERROR_OBJECT_SUBTYPE));
+        }
+        additionalProperties.put(ERROR_OBJECT_SUBTYPE, errorObjectSubtype);
+
         final String invokerFolder = (sourceFolder + '/' + invokerPackage).replace(".", "/");
         final String apiFolder = (sourceFolder + '/' + apiPackage).replace(".", "/");
         final String modelsFolder = (sourceFolder + File.separator + modelPackage().replace('.', File.separatorChar)).replace('/', File.separatorChar);
@@ -1030,6 +1045,14 @@ public class JavaClientCodegen extends AbstractJavaCodegen
         this.gradleProperties= gradleProperties;
     }
 
+    public void setErrorObjectType(final String errorObjectType) {
+        this.errorObjectType= errorObjectType;
+    }
+
+    public void setErrorObjectSubtype(final List<String> errorObjectSubtype) {
+        this.errorObjectSubtype= errorObjectSubtype;
+    }
+
     /**
      * Serialization library.
      *
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson-nextgen/api.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson-nextgen/api.mustache
index 525d56fa5d5..2b623d2cf84 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson-nextgen/api.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson-nextgen/api.mustache
@@ -51,6 +51,7 @@ import java.util.Map;
 import java.io.InputStream;
 {{/supportStreaming}}
 {{/fullJavaUtil}}
+import javax.ws.rs.core.GenericType;
 
 {{#operations}}
 public class {{classname}} {
@@ -294,13 +295,32 @@ public class {{classname}} {
     {{/isDeprecated}}
     public{{/vendorExtensions.x-group-parameters}}{{#vendorExtensions.x-group-parameters}}private{{/vendorExtensions.x-group-parameters}}{{#vendorExtensions.x-streaming}} InputStream {{operationId}}WithHttpInfo({{#allParams}}{{#useBeanValidation}}{{>beanValidationQueryParams}}{{/useBeanValidation}}{{{dataType}}} {{paramName}}{{^-last}}, {{/-last}}{{/allParams}}) throws ApiException {
         okhttp3.Call localVarCall = {{operationId}}ValidateBeforeCall({{#allParams}}{{paramName}}, {{/allParams}}null);
-        {{#returnType}}Type localVarReturnType = new TypeToken<{{{returnType}}}>(){}.getType();
-        return localVarApiClient.executeStream(localVarCall, localVarReturnType);{{/returnType}}
+        {{#returnType}}
+        try {
+            Type localVarReturnType = new TypeToken<{{{returnType}}}>(){}.getType();
+            return localVarApiClient.executeStream(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<{{{errorObjectType}}}{{^errorObjectType}}{{{returnType}}}{{/errorObjectType}}>(){}.getType()));
+            e.setErrorObjectType(new GenericType<{{{errorObjectType}}}{{^errorObjectType}}{{{returnType}}}{{/errorObjectType}}>(){});
+            throw e;
+        }
+        {{/returnType}}
     }
     {{/vendorExtensions.x-streaming}}{{^vendorExtensions.x-streaming}} ApiResponse<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}Void{{/returnType}}> {{operationId}}WithHttpInfo({{#allParams}}{{#useBeanValidation}}{{>beanValidationQueryParams}}{{/useBeanValidation}}{{{dataType}}} {{paramName}}{{^-last}}, {{/-last}}{{/allParams}}) throws ApiException {
         okhttp3.Call localVarCall = {{operationId}}ValidateBeforeCall({{#allParams}}{{paramName}}, {{/allParams}}null);
-        {{#returnType}}Type localVarReturnType = new TypeToken<{{{returnType}}}>(){}.getType();
-        return localVarApiClient.execute(localVarCall, localVarReturnType);{{/returnType}}{{^returnType}}return localVarApiClient.execute(localVarCall);{{/returnType}}
+        {{^returnType}}
+        return localVarApiClient.execute(localVarCall);
+        {{/returnType}}
+        {{#returnType}}
+        try {
+            Type localVarReturnType = new TypeToken<{{{returnType}}}>(){}.getType();
+            return localVarApiClient.execute(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<{{{errorObjectType}}}{{^errorObjectType}}{{{returnType}}}{{/errorObjectType}}>(){}.getType()));
+            e.setErrorObjectType(new GenericType<{{{errorObjectType}}}{{^errorObjectType}}{{{returnType}}}{{/errorObjectType}}>(){});
+            throw e;
+        }
+        {{/returnType}}
     }
     {{/vendorExtensions.x-streaming}}
 
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson-nextgen/apiException.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson-nextgen/apiException.mustache
index 4bec51da938..59da3c51c26 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson-nextgen/apiException.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson-nextgen/apiException.mustache
@@ -9,6 +9,8 @@ import java.util.Map.Entry;
 import java.util.TreeMap;
 {{/caseInsensitiveResponseHeaders}}
 
+import javax.ws.rs.core.GenericType;
+
 /**
  * <p>ApiException class.</p>
  */
@@ -18,6 +20,8 @@ public class ApiException extends{{#useRuntimeException}} RuntimeException {{/us
     private int code = 0;
     private Map<String, List<String>> responseHeaders = null;
     private String responseBody = null;
+    private {{{errorObjectType}}}{{^errorObjectType}}Object{{/errorObjectType}} errorObject = null;
+    private GenericType errorObjectType = null;
  
     /**
      * <p>Constructor for ApiException.</p>
@@ -156,4 +160,40 @@ public class ApiException extends{{#useRuntimeException}} RuntimeException {{/us
     public String getResponseBody() {
         return responseBody;
     }
+
+    /**
+     * Get the error object type.
+     *
+     * @return Error object type
+     */
+    public GenericType getErrorObjectType() {
+        return errorObjectType;
+    }
+
+    /**
+     * Set the error object type.
+     *
+     * @param errorObjectType object type
+     */
+    public void setErrorObjectType(GenericType errorObjectType) {
+        this.errorObjectType = errorObjectType;
+    }
+
+    /**
+     * Get the error object.
+     *
+     * @return Error object
+     */
+    public {{{errorObjectType}}}{{^errorObjectType}}Object{{/errorObjectType}} getErrorObject() {
+        return errorObject;
+    }
+
+    /**
+     * Get the error object.
+     *
+     * @param errorObject Error object
+     */
+    public void setErrorObject({{{errorObjectType}}}{{^errorObjectType}}Object{{/errorObjectType}} errorObject) {
+        this.errorObject = errorObject;
+    }
 }
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson-nextgen/api_doc.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson-nextgen/api_doc.mustache
index 5a4e3969c93..616ad65a5ac 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson-nextgen/api_doc.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson-nextgen/api_doc.mustache
@@ -63,11 +63,23 @@ public class Example {
             .execute();{{/vendorExtensions.x-group-parameters}}{{#returnType}}
       System.out.println(result);{{/returnType}}
     } catch (ApiException e) {
-      System.err.println("Exception when calling {{{classname}}}#{{{operationId}}}");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+      {{=< >=}}
+      <#errorObjectSubtype>
+      <^-first>} else </-first>if (e.getErrorObject() instanceof <&.>) {
+        // do something here
+      <#-last>
+      } else {
+        // something else happened
+        System.err.println("Exception when calling {{{classname}}}#{{{operationId}}}");
+        System.err.println("Status code: " + e.getCode());
+        System.err.println("Reason: " + e.getResponseBody());
+        System.err.println("Response headers: " + e.getResponseHeaders());
+        e.printStackTrace();
+      }
+      </-last>
+      </errorObjectSubtype>
+      <={{ }}=>
+
     }
   }
 }
diff --git a/samples/client/petstore/java/okhttp-gson-nextgen/docs/AnotherFakeApi.md b/samples/client/petstore/java/okhttp-gson-nextgen/docs/AnotherFakeApi.md
index 149488eff9a..af82f73feb6 100644
--- a/samples/client/petstore/java/okhttp-gson-nextgen/docs/AnotherFakeApi.md
+++ b/samples/client/petstore/java/okhttp-gson-nextgen/docs/AnotherFakeApi.md
@@ -35,11 +35,7 @@ public class Example {
       Client result = apiInstance.call123testSpecialTags(client);
       System.out.println(result);
     } catch (ApiException e) {
-      System.err.println("Exception when calling AnotherFakeApi#call123testSpecialTags");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
diff --git a/samples/client/petstore/java/okhttp-gson-nextgen/docs/DefaultApi.md b/samples/client/petstore/java/okhttp-gson-nextgen/docs/DefaultApi.md
index 311c4fa6bbc..c77f189afd0 100644
--- a/samples/client/petstore/java/okhttp-gson-nextgen/docs/DefaultApi.md
+++ b/samples/client/petstore/java/okhttp-gson-nextgen/docs/DefaultApi.md
@@ -32,11 +32,7 @@ public class Example {
       InlineResponseDefault result = apiInstance.fooGet();
       System.out.println(result);
     } catch (ApiException e) {
-      System.err.println("Exception when calling DefaultApi#fooGet");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
diff --git a/samples/client/petstore/java/okhttp-gson-nextgen/docs/FakeApi.md b/samples/client/petstore/java/okhttp-gson-nextgen/docs/FakeApi.md
index 3401bb6eeb0..bee53680247 100644
--- a/samples/client/petstore/java/okhttp-gson-nextgen/docs/FakeApi.md
+++ b/samples/client/petstore/java/okhttp-gson-nextgen/docs/FakeApi.md
@@ -46,11 +46,7 @@ public class Example {
       HealthCheckResult result = apiInstance.fakeHealthGet();
       System.out.println(result);
     } catch (ApiException e) {
-      System.err.println("Exception when calling FakeApi#fakeHealthGet");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -105,11 +101,7 @@ public class Example {
       Boolean result = apiInstance.fakeOuterBooleanSerialize(body);
       System.out.println(result);
     } catch (ApiException e) {
-      System.err.println("Exception when calling FakeApi#fakeOuterBooleanSerialize");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -167,11 +159,7 @@ public class Example {
       OuterComposite result = apiInstance.fakeOuterCompositeSerialize(outerComposite);
       System.out.println(result);
     } catch (ApiException e) {
-      System.err.println("Exception when calling FakeApi#fakeOuterCompositeSerialize");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -229,11 +217,7 @@ public class Example {
       BigDecimal result = apiInstance.fakeOuterNumberSerialize(body);
       System.out.println(result);
     } catch (ApiException e) {
-      System.err.println("Exception when calling FakeApi#fakeOuterNumberSerialize");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -291,11 +275,7 @@ public class Example {
       String result = apiInstance.fakeOuterStringSerialize(body);
       System.out.println(result);
     } catch (ApiException e) {
-      System.err.println("Exception when calling FakeApi#fakeOuterStringSerialize");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -350,11 +330,7 @@ public class Example {
       List<OuterEnum> result = apiInstance.getArrayOfEnums();
       System.out.println(result);
     } catch (ApiException e) {
-      System.err.println("Exception when calling FakeApi#getArrayOfEnums");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -408,11 +384,7 @@ public class Example {
     try {
       apiInstance.testBodyWithFileSchema(fileSchemaTestClass);
     } catch (ApiException e) {
-      System.err.println("Exception when calling FakeApi#testBodyWithFileSchema");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -468,11 +440,7 @@ public class Example {
     try {
       apiInstance.testBodyWithQueryParams(query, user);
     } catch (ApiException e) {
-      System.err.println("Exception when calling FakeApi#testBodyWithQueryParams");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -531,11 +499,7 @@ public class Example {
       Client result = apiInstance.testClientModel(client);
       System.out.println(result);
     } catch (ApiException e) {
-      System.err.println("Exception when calling FakeApi#testClientModel");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -611,11 +575,7 @@ public class Example {
     try {
       apiInstance.testEndpointParameters(number, _double, patternWithoutDelimiter, _byte, integer, int32, int64, _float, string, binary, date, dateTime, password, paramCallback);
     } catch (ApiException e) {
-      System.err.println("Exception when calling FakeApi#testEndpointParameters");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -693,11 +653,7 @@ public class Example {
     try {
       apiInstance.testEnumParameters(enumHeaderStringArray, enumHeaderString, enumQueryStringArray, enumQueryString, enumQueryInteger, enumQueryDouble, enumFormStringArray, enumFormString);
     } catch (ApiException e) {
-      System.err.println("Exception when calling FakeApi#testEnumParameters");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -776,11 +732,7 @@ public class Example {
             .int64Group(int64Group)
             .execute();
     } catch (ApiException e) {
-      System.err.println("Exception when calling FakeApi#testGroupParameters");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -840,11 +792,7 @@ public class Example {
     try {
       apiInstance.testInlineAdditionalProperties(requestBody);
     } catch (ApiException e) {
-      System.err.println("Exception when calling FakeApi#testInlineAdditionalProperties");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -900,11 +848,7 @@ public class Example {
     try {
       apiInstance.testJsonFormData(param, param2);
     } catch (ApiException e) {
-      System.err.println("Exception when calling FakeApi#testJsonFormData");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -966,11 +910,7 @@ public class Example {
     try {
       apiInstance.testQueryParameterCollectionFormat(pipe, ioutil, http, url, context);
     } catch (ApiException e) {
-      System.err.println("Exception when calling FakeApi#testQueryParameterCollectionFormat");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
diff --git a/samples/client/petstore/java/okhttp-gson-nextgen/docs/FakeClassnameTags123Api.md b/samples/client/petstore/java/okhttp-gson-nextgen/docs/FakeClassnameTags123Api.md
index dbd12c37f05..5212d7c7781 100644
--- a/samples/client/petstore/java/okhttp-gson-nextgen/docs/FakeClassnameTags123Api.md
+++ b/samples/client/petstore/java/okhttp-gson-nextgen/docs/FakeClassnameTags123Api.md
@@ -42,11 +42,7 @@ public class Example {
       Client result = apiInstance.testClassname(client);
       System.out.println(result);
     } catch (ApiException e) {
-      System.err.println("Exception when calling FakeClassnameTags123Api#testClassname");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
diff --git a/samples/client/petstore/java/okhttp-gson-nextgen/docs/PetApi.md b/samples/client/petstore/java/okhttp-gson-nextgen/docs/PetApi.md
index cca26664dea..8cdb1506fb5 100644
--- a/samples/client/petstore/java/okhttp-gson-nextgen/docs/PetApi.md
+++ b/samples/client/petstore/java/okhttp-gson-nextgen/docs/PetApi.md
@@ -46,11 +46,7 @@ public class Example {
     try {
       apiInstance.addPet(pet);
     } catch (ApiException e) {
-      System.err.println("Exception when calling PetApi#addPet");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -111,11 +107,7 @@ public class Example {
     try {
       apiInstance.deletePet(petId, apiKey);
     } catch (ApiException e) {
-      System.err.println("Exception when calling PetApi#deletePet");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -180,11 +172,7 @@ public class Example {
       List<Pet> result = apiInstance.findPetsByStatus(status);
       System.out.println(result);
     } catch (ApiException e) {
-      System.err.println("Exception when calling PetApi#findPetsByStatus");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -249,11 +237,7 @@ public class Example {
       List<Pet> result = apiInstance.findPetsByTags(tags);
       System.out.println(result);
     } catch (ApiException e) {
-      System.err.println("Exception when calling PetApi#findPetsByTags");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -319,11 +303,7 @@ public class Example {
       Pet result = apiInstance.getPetById(petId);
       System.out.println(result);
     } catch (ApiException e) {
-      System.err.println("Exception when calling PetApi#getPetById");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -386,11 +366,7 @@ public class Example {
     try {
       apiInstance.updatePet(pet);
     } catch (ApiException e) {
-      System.err.println("Exception when calling PetApi#updatePet");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -454,11 +430,7 @@ public class Example {
     try {
       apiInstance.updatePetWithForm(petId, name, status);
     } catch (ApiException e) {
-      System.err.println("Exception when calling PetApi#updatePetWithForm");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -523,11 +495,7 @@ public class Example {
       ModelApiResponse result = apiInstance.uploadFile(petId, additionalMetadata, file);
       System.out.println(result);
     } catch (ApiException e) {
-      System.err.println("Exception when calling PetApi#uploadFile");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -592,11 +560,7 @@ public class Example {
       ModelApiResponse result = apiInstance.uploadFileWithRequiredFile(petId, requiredFile, additionalMetadata);
       System.out.println(result);
     } catch (ApiException e) {
-      System.err.println("Exception when calling PetApi#uploadFileWithRequiredFile");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
diff --git a/samples/client/petstore/java/okhttp-gson-nextgen/docs/StoreApi.md b/samples/client/petstore/java/okhttp-gson-nextgen/docs/StoreApi.md
index 270388f5e44..8d9dee8e68f 100644
--- a/samples/client/petstore/java/okhttp-gson-nextgen/docs/StoreApi.md
+++ b/samples/client/petstore/java/okhttp-gson-nextgen/docs/StoreApi.md
@@ -37,11 +37,7 @@ public class Example {
     try {
       apiInstance.deleteOrder(orderId);
     } catch (ApiException e) {
-      System.err.println("Exception when calling StoreApi#deleteOrder");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -106,11 +102,7 @@ public class Example {
       Map<String, Integer> result = apiInstance.getInventory();
       System.out.println(result);
     } catch (ApiException e) {
-      System.err.println("Exception when calling StoreApi#getInventory");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -165,11 +157,7 @@ public class Example {
       Order result = apiInstance.getOrderById(orderId);
       System.out.println(result);
     } catch (ApiException e) {
-      System.err.println("Exception when calling StoreApi#getOrderById");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -227,11 +215,7 @@ public class Example {
       Order result = apiInstance.placeOrder(order);
       System.out.println(result);
     } catch (ApiException e) {
-      System.err.println("Exception when calling StoreApi#placeOrder");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
diff --git a/samples/client/petstore/java/okhttp-gson-nextgen/docs/UserApi.md b/samples/client/petstore/java/okhttp-gson-nextgen/docs/UserApi.md
index 26a0642e323..5c8ee4c6f5e 100644
--- a/samples/client/petstore/java/okhttp-gson-nextgen/docs/UserApi.md
+++ b/samples/client/petstore/java/okhttp-gson-nextgen/docs/UserApi.md
@@ -41,11 +41,7 @@ public class Example {
     try {
       apiInstance.createUser(user);
     } catch (ApiException e) {
-      System.err.println("Exception when calling UserApi#createUser");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -100,11 +96,7 @@ public class Example {
     try {
       apiInstance.createUsersWithArrayInput(user);
     } catch (ApiException e) {
-      System.err.println("Exception when calling UserApi#createUsersWithArrayInput");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -159,11 +151,7 @@ public class Example {
     try {
       apiInstance.createUsersWithListInput(user);
     } catch (ApiException e) {
-      System.err.println("Exception when calling UserApi#createUsersWithListInput");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -220,11 +208,7 @@ public class Example {
     try {
       apiInstance.deleteUser(username);
     } catch (ApiException e) {
-      System.err.println("Exception when calling UserApi#deleteUser");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -281,11 +265,7 @@ public class Example {
       User result = apiInstance.getUserByName(username);
       System.out.println(result);
     } catch (ApiException e) {
-      System.err.println("Exception when calling UserApi#getUserByName");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -344,11 +324,7 @@ public class Example {
       String result = apiInstance.loginUser(username, password);
       System.out.println(result);
     } catch (ApiException e) {
-      System.err.println("Exception when calling UserApi#loginUser");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -404,11 +380,7 @@ public class Example {
     try {
       apiInstance.logoutUser();
     } catch (ApiException e) {
-      System.err.println("Exception when calling UserApi#logoutUser");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
@@ -463,11 +435,7 @@ public class Example {
     try {
       apiInstance.updateUser(username, user);
     } catch (ApiException e) {
-      System.err.println("Exception when calling UserApi#updateUser");
-      System.err.println("Status code: " + e.getCode());
-      System.err.println("Reason: " + e.getResponseBody());
-      System.err.println("Response headers: " + e.getResponseHeaders());
-      e.printStackTrace();
+
     }
   }
 }
diff --git a/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/ApiException.java b/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/ApiException.java
index 5851f0405ad..60e4f9a5e7e 100644
--- a/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/ApiException.java
+++ b/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/ApiException.java
@@ -16,6 +16,8 @@ package org.openapitools.client;
 import java.util.Map;
 import java.util.List;
 
+import javax.ws.rs.core.GenericType;
+
 /**
  * <p>ApiException class.</p>
  */
@@ -25,6 +27,8 @@ public class ApiException extends Exception {
     private int code = 0;
     private Map<String, List<String>> responseHeaders = null;
     private String responseBody = null;
+    private Object errorObject = null;
+    private GenericType errorObjectType = null;
  
     /**
      * <p>Constructor for ApiException.</p>
@@ -151,4 +155,40 @@ public class ApiException extends Exception {
     public String getResponseBody() {
         return responseBody;
     }
+
+    /**
+     * Get the error object type.
+     *
+     * @return Error object type
+     */
+    public GenericType getErrorObjectType() {
+        return errorObjectType;
+    }
+
+    /**
+     * Set the error object type.
+     *
+     * @param errorObjectType object type
+     */
+    public void setErrorObjectType(GenericType errorObjectType) {
+        this.errorObjectType = errorObjectType;
+    }
+
+    /**
+     * Get the error object.
+     *
+     * @return Error object
+     */
+    public Object getErrorObject() {
+        return errorObject;
+    }
+
+    /**
+     * Get the error object.
+     *
+     * @param errorObject Error object
+     */
+    public void setErrorObject(Object errorObject) {
+        this.errorObject = errorObject;
+    }
 }
diff --git a/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/AnotherFakeApi.java b/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
index e258256633e..b0269aea9fc 100644
--- a/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
+++ b/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
@@ -34,6 +34,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import javax.ws.rs.core.GenericType;
 
 public class AnotherFakeApi {
     private ApiClient localVarApiClient;
@@ -143,8 +144,14 @@ public class AnotherFakeApi {
      */
     public ApiResponse<Client> call123testSpecialTagsWithHttpInfo(Client client) throws ApiException {
         okhttp3.Call localVarCall = call123testSpecialTagsValidateBeforeCall(client, null);
-        Type localVarReturnType = new TypeToken<Client>(){}.getType();
-        return localVarApiClient.execute(localVarCall, localVarReturnType);
+        try {
+            Type localVarReturnType = new TypeToken<Client>(){}.getType();
+            return localVarApiClient.execute(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<Client>(){}.getType()));
+            e.setErrorObjectType(new GenericType<Client>(){});
+            throw e;
+        }
     }
 
     /**
diff --git a/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/DefaultApi.java b/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/DefaultApi.java
index c4e26ea2b1c..1c8e2d24856 100644
--- a/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/DefaultApi.java
+++ b/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/DefaultApi.java
@@ -34,6 +34,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import javax.ws.rs.core.GenericType;
 
 public class DefaultApi {
     private ApiClient localVarApiClient;
@@ -135,8 +136,14 @@ public class DefaultApi {
      */
     public ApiResponse<InlineResponseDefault> fooGetWithHttpInfo() throws ApiException {
         okhttp3.Call localVarCall = fooGetValidateBeforeCall(null);
-        Type localVarReturnType = new TypeToken<InlineResponseDefault>(){}.getType();
-        return localVarApiClient.execute(localVarCall, localVarReturnType);
+        try {
+            Type localVarReturnType = new TypeToken<InlineResponseDefault>(){}.getType();
+            return localVarApiClient.execute(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<InlineResponseDefault>(){}.getType()));
+            e.setErrorObjectType(new GenericType<InlineResponseDefault>(){});
+            throw e;
+        }
     }
 
     /**
diff --git a/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/FakeApi.java
index 3c5114fef1b..271df76973e 100644
--- a/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -43,6 +43,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import javax.ws.rs.core.GenericType;
 
 public class FakeApi {
     private ApiClient localVarApiClient;
@@ -144,8 +145,14 @@ public class FakeApi {
      */
     public ApiResponse<HealthCheckResult> fakeHealthGetWithHttpInfo() throws ApiException {
         okhttp3.Call localVarCall = fakeHealthGetValidateBeforeCall(null);
-        Type localVarReturnType = new TypeToken<HealthCheckResult>(){}.getType();
-        return localVarApiClient.execute(localVarCall, localVarReturnType);
+        try {
+            Type localVarReturnType = new TypeToken<HealthCheckResult>(){}.getType();
+            return localVarApiClient.execute(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<HealthCheckResult>(){}.getType()));
+            e.setErrorObjectType(new GenericType<HealthCheckResult>(){});
+            throw e;
+        }
     }
 
     /**
@@ -251,8 +258,14 @@ public class FakeApi {
      */
     public ApiResponse<Boolean> fakeOuterBooleanSerializeWithHttpInfo(Boolean body) throws ApiException {
         okhttp3.Call localVarCall = fakeOuterBooleanSerializeValidateBeforeCall(body, null);
-        Type localVarReturnType = new TypeToken<Boolean>(){}.getType();
-        return localVarApiClient.execute(localVarCall, localVarReturnType);
+        try {
+            Type localVarReturnType = new TypeToken<Boolean>(){}.getType();
+            return localVarApiClient.execute(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<Boolean>(){}.getType()));
+            e.setErrorObjectType(new GenericType<Boolean>(){});
+            throw e;
+        }
     }
 
     /**
@@ -359,8 +372,14 @@ public class FakeApi {
      */
     public ApiResponse<OuterComposite> fakeOuterCompositeSerializeWithHttpInfo(OuterComposite outerComposite) throws ApiException {
         okhttp3.Call localVarCall = fakeOuterCompositeSerializeValidateBeforeCall(outerComposite, null);
-        Type localVarReturnType = new TypeToken<OuterComposite>(){}.getType();
-        return localVarApiClient.execute(localVarCall, localVarReturnType);
+        try {
+            Type localVarReturnType = new TypeToken<OuterComposite>(){}.getType();
+            return localVarApiClient.execute(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<OuterComposite>(){}.getType()));
+            e.setErrorObjectType(new GenericType<OuterComposite>(){});
+            throw e;
+        }
     }
 
     /**
@@ -467,8 +486,14 @@ public class FakeApi {
      */
     public ApiResponse<BigDecimal> fakeOuterNumberSerializeWithHttpInfo(BigDecimal body) throws ApiException {
         okhttp3.Call localVarCall = fakeOuterNumberSerializeValidateBeforeCall(body, null);
-        Type localVarReturnType = new TypeToken<BigDecimal>(){}.getType();
-        return localVarApiClient.execute(localVarCall, localVarReturnType);
+        try {
+            Type localVarReturnType = new TypeToken<BigDecimal>(){}.getType();
+            return localVarApiClient.execute(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<BigDecimal>(){}.getType()));
+            e.setErrorObjectType(new GenericType<BigDecimal>(){});
+            throw e;
+        }
     }
 
     /**
@@ -575,8 +600,14 @@ public class FakeApi {
      */
     public ApiResponse<String> fakeOuterStringSerializeWithHttpInfo(String body) throws ApiException {
         okhttp3.Call localVarCall = fakeOuterStringSerializeValidateBeforeCall(body, null);
-        Type localVarReturnType = new TypeToken<String>(){}.getType();
-        return localVarApiClient.execute(localVarCall, localVarReturnType);
+        try {
+            Type localVarReturnType = new TypeToken<String>(){}.getType();
+            return localVarApiClient.execute(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<String>(){}.getType()));
+            e.setErrorObjectType(new GenericType<String>(){});
+            throw e;
+        }
     }
 
     /**
@@ -680,8 +711,14 @@ public class FakeApi {
      */
     public ApiResponse<List<OuterEnum>> getArrayOfEnumsWithHttpInfo() throws ApiException {
         okhttp3.Call localVarCall = getArrayOfEnumsValidateBeforeCall(null);
-        Type localVarReturnType = new TypeToken<List<OuterEnum>>(){}.getType();
-        return localVarApiClient.execute(localVarCall, localVarReturnType);
+        try {
+            Type localVarReturnType = new TypeToken<List<OuterEnum>>(){}.getType();
+            return localVarApiClient.execute(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<List<OuterEnum>>(){}.getType()));
+            e.setErrorObjectType(new GenericType<List<OuterEnum>>(){});
+            throw e;
+        }
     }
 
     /**
@@ -1023,8 +1060,14 @@ public class FakeApi {
      */
     public ApiResponse<Client> testClientModelWithHttpInfo(Client client) throws ApiException {
         okhttp3.Call localVarCall = testClientModelValidateBeforeCall(client, null);
-        Type localVarReturnType = new TypeToken<Client>(){}.getType();
-        return localVarApiClient.execute(localVarCall, localVarReturnType);
+        try {
+            Type localVarReturnType = new TypeToken<Client>(){}.getType();
+            return localVarApiClient.execute(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<Client>(){}.getType()));
+            e.setErrorObjectType(new GenericType<Client>(){});
+            throw e;
+        }
     }
 
     /**
diff --git a/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java b/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
index f9449ed4420..db7a5f435f4 100644
--- a/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
+++ b/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
@@ -34,6 +34,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import javax.ws.rs.core.GenericType;
 
 public class FakeClassnameTags123Api {
     private ApiClient localVarApiClient;
@@ -143,8 +144,14 @@ public class FakeClassnameTags123Api {
      */
     public ApiResponse<Client> testClassnameWithHttpInfo(Client client) throws ApiException {
         okhttp3.Call localVarCall = testClassnameValidateBeforeCall(client, null);
-        Type localVarReturnType = new TypeToken<Client>(){}.getType();
-        return localVarApiClient.execute(localVarCall, localVarReturnType);
+        try {
+            Type localVarReturnType = new TypeToken<Client>(){}.getType();
+            return localVarApiClient.execute(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<Client>(){}.getType()));
+            e.setErrorObjectType(new GenericType<Client>(){});
+            throw e;
+        }
     }
 
     /**
diff --git a/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/PetApi.java b/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/PetApi.java
index d88ee6f9c31..98d73aa76f0 100644
--- a/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/PetApi.java
+++ b/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/PetApi.java
@@ -36,6 +36,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import javax.ws.rs.core.GenericType;
 
 public class PetApi {
     private ApiClient localVarApiClient;
@@ -379,8 +380,14 @@ public class PetApi {
      */
     public ApiResponse<List<Pet>> findPetsByStatusWithHttpInfo(List<String> status) throws ApiException {
         okhttp3.Call localVarCall = findPetsByStatusValidateBeforeCall(status, null);
-        Type localVarReturnType = new TypeToken<List<Pet>>(){}.getType();
-        return localVarApiClient.execute(localVarCall, localVarReturnType);
+        try {
+            Type localVarReturnType = new TypeToken<List<Pet>>(){}.getType();
+            return localVarApiClient.execute(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<List<Pet>>(){}.getType()));
+            e.setErrorObjectType(new GenericType<List<Pet>>(){});
+            throw e;
+        }
     }
 
     /**
@@ -507,8 +514,14 @@ public class PetApi {
     @Deprecated
     public ApiResponse<List<Pet>> findPetsByTagsWithHttpInfo(List<String> tags) throws ApiException {
         okhttp3.Call localVarCall = findPetsByTagsValidateBeforeCall(tags, null);
-        Type localVarReturnType = new TypeToken<List<Pet>>(){}.getType();
-        return localVarApiClient.execute(localVarCall, localVarReturnType);
+        try {
+            Type localVarReturnType = new TypeToken<List<Pet>>(){}.getType();
+            return localVarApiClient.execute(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<List<Pet>>(){}.getType()));
+            e.setErrorObjectType(new GenericType<List<Pet>>(){});
+            throw e;
+        }
     }
 
     /**
@@ -630,8 +643,14 @@ public class PetApi {
      */
     public ApiResponse<Pet> getPetByIdWithHttpInfo(Long petId) throws ApiException {
         okhttp3.Call localVarCall = getPetByIdValidateBeforeCall(petId, null);
-        Type localVarReturnType = new TypeToken<Pet>(){}.getType();
-        return localVarApiClient.execute(localVarCall, localVarReturnType);
+        try {
+            Type localVarReturnType = new TypeToken<Pet>(){}.getType();
+            return localVarApiClient.execute(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<Pet>(){}.getType()));
+            e.setErrorObjectType(new GenericType<Pet>(){});
+            throw e;
+        }
     }
 
     /**
@@ -1003,8 +1022,14 @@ public class PetApi {
      */
     public ApiResponse<ModelApiResponse> uploadFileWithHttpInfo(Long petId, String additionalMetadata, File file) throws ApiException {
         okhttp3.Call localVarCall = uploadFileValidateBeforeCall(petId, additionalMetadata, file, null);
-        Type localVarReturnType = new TypeToken<ModelApiResponse>(){}.getType();
-        return localVarApiClient.execute(localVarCall, localVarReturnType);
+        try {
+            Type localVarReturnType = new TypeToken<ModelApiResponse>(){}.getType();
+            return localVarApiClient.execute(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<ModelApiResponse>(){}.getType()));
+            e.setErrorObjectType(new GenericType<ModelApiResponse>(){});
+            throw e;
+        }
     }
 
     /**
@@ -1138,8 +1163,14 @@ public class PetApi {
      */
     public ApiResponse<ModelApiResponse> uploadFileWithRequiredFileWithHttpInfo(Long petId, File requiredFile, String additionalMetadata) throws ApiException {
         okhttp3.Call localVarCall = uploadFileWithRequiredFileValidateBeforeCall(petId, requiredFile, additionalMetadata, null);
-        Type localVarReturnType = new TypeToken<ModelApiResponse>(){}.getType();
-        return localVarApiClient.execute(localVarCall, localVarReturnType);
+        try {
+            Type localVarReturnType = new TypeToken<ModelApiResponse>(){}.getType();
+            return localVarApiClient.execute(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<ModelApiResponse>(){}.getType()));
+            e.setErrorObjectType(new GenericType<ModelApiResponse>(){});
+            throw e;
+        }
     }
 
     /**
diff --git a/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/StoreApi.java b/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/StoreApi.java
index d9a068df9e9..ab5718fb99c 100644
--- a/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/StoreApi.java
+++ b/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/StoreApi.java
@@ -34,6 +34,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import javax.ws.rs.core.GenericType;
 
 public class StoreApi {
     private ApiClient localVarApiClient;
@@ -249,8 +250,14 @@ public class StoreApi {
      */
     public ApiResponse<Map<String, Integer>> getInventoryWithHttpInfo() throws ApiException {
         okhttp3.Call localVarCall = getInventoryValidateBeforeCall(null);
-        Type localVarReturnType = new TypeToken<Map<String, Integer>>(){}.getType();
-        return localVarApiClient.execute(localVarCall, localVarReturnType);
+        try {
+            Type localVarReturnType = new TypeToken<Map<String, Integer>>(){}.getType();
+            return localVarApiClient.execute(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<Map<String, Integer>>(){}.getType()));
+            e.setErrorObjectType(new GenericType<Map<String, Integer>>(){});
+            throw e;
+        }
     }
 
     /**
@@ -368,8 +375,14 @@ public class StoreApi {
      */
     public ApiResponse<Order> getOrderByIdWithHttpInfo(Long orderId) throws ApiException {
         okhttp3.Call localVarCall = getOrderByIdValidateBeforeCall(orderId, null);
-        Type localVarReturnType = new TypeToken<Order>(){}.getType();
-        return localVarApiClient.execute(localVarCall, localVarReturnType);
+        try {
+            Type localVarReturnType = new TypeToken<Order>(){}.getType();
+            return localVarApiClient.execute(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<Order>(){}.getType()));
+            e.setErrorObjectType(new GenericType<Order>(){});
+            throw e;
+        }
     }
 
     /**
@@ -486,8 +499,14 @@ public class StoreApi {
      */
     public ApiResponse<Order> placeOrderWithHttpInfo(Order order) throws ApiException {
         okhttp3.Call localVarCall = placeOrderValidateBeforeCall(order, null);
-        Type localVarReturnType = new TypeToken<Order>(){}.getType();
-        return localVarApiClient.execute(localVarCall, localVarReturnType);
+        try {
+            Type localVarReturnType = new TypeToken<Order>(){}.getType();
+            return localVarApiClient.execute(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<Order>(){}.getType()));
+            e.setErrorObjectType(new GenericType<Order>(){});
+            throw e;
+        }
     }
 
     /**
diff --git a/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/UserApi.java b/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/UserApi.java
index 0f4f2d294a4..4bf2dc2b82f 100644
--- a/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/UserApi.java
+++ b/samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/api/UserApi.java
@@ -34,6 +34,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import javax.ws.rs.core.GenericType;
 
 public class UserApi {
     private ApiClient localVarApiClient;
@@ -591,8 +592,14 @@ public class UserApi {
      */
     public ApiResponse<User> getUserByNameWithHttpInfo(String username) throws ApiException {
         okhttp3.Call localVarCall = getUserByNameValidateBeforeCall(username, null);
-        Type localVarReturnType = new TypeToken<User>(){}.getType();
-        return localVarApiClient.execute(localVarCall, localVarReturnType);
+        try {
+            Type localVarReturnType = new TypeToken<User>(){}.getType();
+            return localVarApiClient.execute(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<User>(){}.getType()));
+            e.setErrorObjectType(new GenericType<User>(){});
+            throw e;
+        }
     }
 
     /**
@@ -725,8 +732,14 @@ public class UserApi {
      */
     public ApiResponse<String> loginUserWithHttpInfo(String username, String password) throws ApiException {
         okhttp3.Call localVarCall = loginUserValidateBeforeCall(username, password, null);
-        Type localVarReturnType = new TypeToken<String>(){}.getType();
-        return localVarApiClient.execute(localVarCall, localVarReturnType);
+        try {
+            Type localVarReturnType = new TypeToken<String>(){}.getType();
+            return localVarApiClient.execute(localVarCall, localVarReturnType);
+        } catch (ApiException e) {
+            e.setErrorObject(localVarApiClient.getJSON().getGson().fromJson(e.getResponseBody(), new TypeToken<String>(){}.getType()));
+            e.setErrorObjectType(new GenericType<String>(){});
+            throw e;
+        }
     }
 
     /**