diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/ApiClient.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/ApiClient.mustache
index 430783443435..df21df17b02b 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/ApiClient.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/ApiClient.mustache
@@ -99,9 +99,6 @@ public class ApiClient {
 
     private Map<String, Authentication> authentications;
 
-    private HttpStatus statusCode;
-    private MultiValueMap<String, String> responseHeaders;
-
     private DateFormat dateFormat;
 
     public ApiClient() {
@@ -154,22 +151,6 @@ public class ApiClient {
         return this;
     }
 
-    /**
-     * Gets the status code of the previous request
-     * @return HttpStatus the status code
-     */
-    public HttpStatus getStatusCode() {
-        return statusCode;
-    }
-
-    /**
-     * Gets the response headers of the previous request
-     * @return MultiValueMap a map of response headers
-     */
-    public MultiValueMap<String, String> getResponseHeaders() {
-        return responseHeaders;
-    }
-
     /**
      * Get authentications (key: authentication name, value: authentication).
      * @return Map the currently configured authentication types
@@ -580,9 +561,9 @@ public class ApiClient {
      * @param contentType The request's Content-Type header
      * @param authNames The authentications to apply
      * @param returnType The return type into which to deserialize the response
-     * @return The response body in chosen type
+     * @return ResponseEntity&lt;T&gt; The response of the chosen type
      */
-    public <T> T invokeAPI(String path, HttpMethod method, MultiValueMap<String, String> queryParams, Object body, HttpHeaders headerParams, MultiValueMap<String, Object> formParams, List<MediaType> accept, MediaType contentType, String[] authNames, ParameterizedTypeReference<T> returnType) throws RestClientException {
+    public <T> ResponseEntity<T> invokeAPI(String path, HttpMethod method, MultiValueMap<String, String> queryParams, Object body, HttpHeaders headerParams, MultiValueMap<String, Object> formParams, List<MediaType> accept, MediaType contentType, String[] authNames, ParameterizedTypeReference<T> returnType) throws RestClientException {
         updateParamsForAuth(authNames, queryParams, headerParams);
 
         final UriComponentsBuilder builder = UriComponentsBuilder.fromHttpUrl(basePath).path(path);
@@ -624,16 +605,11 @@ public class ApiClient {
 
         ResponseEntity<T> responseEntity = restTemplate.exchange(requestEntity, returnType);
 
-        statusCode = responseEntity.getStatusCode();
-        responseHeaders = responseEntity.getHeaders();
-
-        if (responseEntity.getStatusCode() == HttpStatus.NO_CONTENT) {
-            return null;
-        } else if (responseEntity.getStatusCode().is2xxSuccessful()) {
-            return responseEntity.getBody();
+        if (responseEntity.getStatusCode().is2xxSuccessful()) {
+            return responseEntity;
         } else {
             // The error handler built into the RestTemplate should handle 400 and 500 series errors.
-            throw new RestClientException("API returned " + statusCode + " and it wasn't handled by the RestTemplate error handler");
+            throw new RestClientException("API returned " + responseEntity.getStatusCode() + " and it wasn't handled by the RestTemplate error handler");
         }
     }
 
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/api.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/api.mustache
index 79cdcd51ac1b..61a0d5272044 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/api.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/api.mustache
@@ -25,6 +25,7 @@ import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
 
 {{>generatedAnnotation}}
 @Component("{{package}}.{{classname}}")
@@ -53,16 +54,53 @@ public class {{classname}} {
     /**
      * {{summary}}
      * {{notes}}
-{{#responses}}     * <p><b>{{code}}</b>{{#message}} - {{message}}{{/message}}
-{{/responses}}{{#allParams}}     * @param {{paramName}} {{description}}{{^description}}The {{paramName}} parameter{{/description}}
-{{/allParams}}{{#returnType}}     * @return {{returnType}}
-{{/returnType}}     * @throws RestClientException if an error occurs while attempting to invoke the API
-{{#externalDocs}}
-    * {{description}}
-    * @see <a href="{{url}}">{{summary}} Documentation</a>
-{{/externalDocs}}
+    {{#responses}}
+     * <p><b>{{code}}</b>{{#message}} - {{message}}{{/message}}
+     {{/responses}}
+     {{#allParams}}
+     * @param {{paramName}} {{description}}{{#required}} (required){{/required}}{{^required}} (optional{{#defaultValue}}, default to {{.}}{{/defaultValue}}){{/required}}
+     {{/allParams}}
+     {{#returnType}}
+     * @return {{returnType}}
+     {{/returnType}}
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     {{#externalDocs}}
+     * {{description}}
+     * @see <a href="{{url}}">{{summary}} Documentation</a>
+     {{/externalDocs}}
      */
+    {{#isDeprecated}}
+    @Deprecated
+    {{/isDeprecated}}
     public {{#returnType}}{{{returnType}}} {{/returnType}}{{^returnType}}void {{/returnType}}{{operationId}}({{#allParams}}{{{dataType}}} {{paramName}}{{#hasMore}}, {{/hasMore}}{{/allParams}}) throws RestClientException {
+        {{#returnType}}
+        return {{operationId}}WithHttpInfo({{#allParams}}{{paramName}}{{#hasMore}}, {{/hasMore}}{{/allParams}}).getBody();
+        {{/returnType}}
+        {{^returnType}}
+        {{operationId}}WithHttpInfo({{#allParams}}{{paramName}}{{#hasMore}}, {{/hasMore}}{{/allParams}});
+        {{/returnType}}
+    }
+
+    /**
+     * {{summary}}
+     * {{notes}}
+     {{#responses}}
+     * <p><b>{{code}}</b>{{#message}} - {{message}}{{/message}}
+     {{/responses}}
+     {{#allParams}}
+     * @param {{paramName}} {{description}}{{#required}} (required){{/required}}{{^required}} (optional{{#defaultValue}}, default to {{.}}{{/defaultValue}}){{/required}}
+     {{/allParams}}
+     * @return ResponseEntity&lt;{{#returnType}}{{returnType}}{{/returnType}}{{^returnType}}Void{{/returnType}}&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     {{#externalDocs}}
+     * {{description}}
+     * @see <a href="{{url}}">{{summary}} Documentation</a>
+     {{/externalDocs}}
+     */
+    {{#isDeprecated}}
+    @Deprecated
+    {{/isDeprecated}}
+    public ResponseEntity<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}Void{{/returnType}}> {{operationId}}WithHttpInfo({{#allParams}}{{{dataType}}} {{paramName}}{{#hasMore}}, {{/hasMore}}{{/allParams}}) throws RestClientException {
         Object postBody = {{#bodyParam}}{{paramName}}{{/bodyParam}}{{^bodyParam}}null{{/bodyParam}};
         {{#allParams}}{{#required}}
         // verify the required parameter '{{paramName}}' is set
@@ -102,7 +140,7 @@ public class {{classname}} {
         String[] authNames = new String[] { {{#authMethods}}"{{name}}"{{#hasMore}}, {{/hasMore}}{{/authMethods}} };
 
         {{#returnType}}ParameterizedTypeReference<{{{returnType}}}> returnType = new ParameterizedTypeReference<{{{returnType}}}>() {};{{/returnType}}{{^returnType}}ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};{{/returnType}}
-        {{#returnType}}return {{/returnType}}apiClient.invokeAPI(path, HttpMethod.{{httpMethod}}, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.{{httpMethod}}, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     {{/operation}}
 }
diff --git a/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/ApiClient.java
index 5d8fa7b9a8ed..007c0b9d7ad4 100644
--- a/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/ApiClient.java
@@ -91,9 +91,6 @@ private String collectionToString(Collection<? extends CharSequence> collection)
 
     private Map<String, Authentication> authentications;
 
-    private HttpStatus statusCode;
-    private MultiValueMap<String, String> responseHeaders;
-
     private DateFormat dateFormat;
 
     public ApiClient() {
@@ -146,22 +143,6 @@ public ApiClient setBasePath(String basePath) {
         return this;
     }
 
-    /**
-     * Gets the status code of the previous request
-     * @return HttpStatus the status code
-     */
-    public HttpStatus getStatusCode() {
-        return statusCode;
-    }
-
-    /**
-     * Gets the response headers of the previous request
-     * @return MultiValueMap a map of response headers
-     */
-    public MultiValueMap<String, String> getResponseHeaders() {
-        return responseHeaders;
-    }
-
     /**
      * Get authentications (key: authentication name, value: authentication).
      * @return Map the currently configured authentication types
@@ -568,9 +549,9 @@ public String expandPath(String pathTemplate, Map<String, Object> variables) {
      * @param contentType The request's Content-Type header
      * @param authNames The authentications to apply
      * @param returnType The return type into which to deserialize the response
-     * @return The response body in chosen type
+     * @return ResponseEntity&lt;T&gt; The response of the chosen type
      */
-    public <T> T invokeAPI(String path, HttpMethod method, MultiValueMap<String, String> queryParams, Object body, HttpHeaders headerParams, MultiValueMap<String, Object> formParams, List<MediaType> accept, MediaType contentType, String[] authNames, ParameterizedTypeReference<T> returnType) throws RestClientException {
+    public <T> ResponseEntity<T> invokeAPI(String path, HttpMethod method, MultiValueMap<String, String> queryParams, Object body, HttpHeaders headerParams, MultiValueMap<String, Object> formParams, List<MediaType> accept, MediaType contentType, String[] authNames, ParameterizedTypeReference<T> returnType) throws RestClientException {
         updateParamsForAuth(authNames, queryParams, headerParams);
 
         final UriComponentsBuilder builder = UriComponentsBuilder.fromHttpUrl(basePath).path(path);
@@ -612,16 +593,11 @@ public <T> T invokeAPI(String path, HttpMethod method, MultiValueMap<String, Str
 
         ResponseEntity<T> responseEntity = restTemplate.exchange(requestEntity, returnType);
 
-        statusCode = responseEntity.getStatusCode();
-        responseHeaders = responseEntity.getHeaders();
-
-        if (responseEntity.getStatusCode() == HttpStatus.NO_CONTENT) {
-            return null;
-        } else if (responseEntity.getStatusCode().is2xxSuccessful()) {
-            return responseEntity.getBody();
+        if (responseEntity.getStatusCode().is2xxSuccessful()) {
+            return responseEntity;
         } else {
             // The error handler built into the RestTemplate should handle 400 and 500 series errors.
-            throw new RestClientException("API returned " + statusCode + " and it wasn't handled by the RestTemplate error handler");
+            throw new RestClientException("API returned " + responseEntity.getStatusCode() + " and it wasn't handled by the RestTemplate error handler");
         }
     }
 
diff --git a/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/AnotherFakeApi.java b/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
index ffb5afa7d047..542171d1d507 100644
--- a/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
+++ b/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
@@ -24,6 +24,7 @@
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
 
 
 @Component("org.openapitools.client.api.AnotherFakeApi")
@@ -51,11 +52,23 @@ public void setApiClient(ApiClient apiClient) {
      * To test special tags
      * To test special tags and operation ID starting with number
      * <p><b>200</b> - successful operation
-     * @param body client model
+     * @param body client model (required)
      * @return Client
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public Client call123testSpecialTags(Client body) throws RestClientException {
+        return call123testSpecialTagsWithHttpInfo(body).getBody();
+    }
+
+    /**
+     * To test special tags
+     * To test special tags and operation ID starting with number
+     * <p><b>200</b> - successful operation
+     * @param body client model (required)
+     * @return ResponseEntity&lt;Client&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Client> call123testSpecialTagsWithHttpInfo(Client body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'body' is set
diff --git a/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/FakeApi.java
index 8b7f1118e5f7..73d0e62ffaa3 100644
--- a/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -32,6 +32,7 @@
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
 
 
 @Component("org.openapitools.client.api.FakeApi")
@@ -59,10 +60,22 @@ public void setApiClient(ApiClient apiClient) {
      * creates an XmlItem
      * this route creates an XmlItem
      * <p><b>200</b> - successful operation
-     * @param xmlItem XmlItem Body
+     * @param xmlItem XmlItem Body (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void createXmlItem(XmlItem xmlItem) throws RestClientException {
+        createXmlItemWithHttpInfo(xmlItem);
+    }
+
+    /**
+     * creates an XmlItem
+     * this route creates an XmlItem
+     * <p><b>200</b> - successful operation
+     * @param xmlItem XmlItem Body (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> createXmlItemWithHttpInfo(XmlItem xmlItem) throws RestClientException {
         Object postBody = xmlItem;
         
         // verify the required parameter 'xmlItem' is set
@@ -86,17 +99,29 @@ public void createXmlItem(XmlItem xmlItem) throws RestClientException {
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * 
      * Test serialization of outer boolean types
      * <p><b>200</b> - Output boolean
-     * @param body Input boolean as post body
+     * @param body Input boolean as post body (optional)
      * @return Boolean
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public Boolean fakeOuterBooleanSerialize(Boolean body) throws RestClientException {
+        return fakeOuterBooleanSerializeWithHttpInfo(body).getBody();
+    }
+
+    /**
+     * 
+     * Test serialization of outer boolean types
+     * <p><b>200</b> - Output boolean
+     * @param body Input boolean as post body (optional)
+     * @return ResponseEntity&lt;Boolean&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Boolean> fakeOuterBooleanSerializeWithHttpInfo(Boolean body) throws RestClientException {
         Object postBody = body;
         
         String path = apiClient.expandPath("/fake/outer/boolean", Collections.<String, Object>emptyMap());
@@ -121,11 +146,23 @@ public Boolean fakeOuterBooleanSerialize(Boolean body) throws RestClientExceptio
      * 
      * Test serialization of object with outer number type
      * <p><b>200</b> - Output composite
-     * @param body Input composite as post body
+     * @param body Input composite as post body (optional)
      * @return OuterComposite
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public OuterComposite fakeOuterCompositeSerialize(OuterComposite body) throws RestClientException {
+        return fakeOuterCompositeSerializeWithHttpInfo(body).getBody();
+    }
+
+    /**
+     * 
+     * Test serialization of object with outer number type
+     * <p><b>200</b> - Output composite
+     * @param body Input composite as post body (optional)
+     * @return ResponseEntity&lt;OuterComposite&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<OuterComposite> fakeOuterCompositeSerializeWithHttpInfo(OuterComposite body) throws RestClientException {
         Object postBody = body;
         
         String path = apiClient.expandPath("/fake/outer/composite", Collections.<String, Object>emptyMap());
@@ -150,11 +187,23 @@ public OuterComposite fakeOuterCompositeSerialize(OuterComposite body) throws Re
      * 
      * Test serialization of outer number types
      * <p><b>200</b> - Output number
-     * @param body Input number as post body
+     * @param body Input number as post body (optional)
      * @return BigDecimal
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public BigDecimal fakeOuterNumberSerialize(BigDecimal body) throws RestClientException {
+        return fakeOuterNumberSerializeWithHttpInfo(body).getBody();
+    }
+
+    /**
+     * 
+     * Test serialization of outer number types
+     * <p><b>200</b> - Output number
+     * @param body Input number as post body (optional)
+     * @return ResponseEntity&lt;BigDecimal&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<BigDecimal> fakeOuterNumberSerializeWithHttpInfo(BigDecimal body) throws RestClientException {
         Object postBody = body;
         
         String path = apiClient.expandPath("/fake/outer/number", Collections.<String, Object>emptyMap());
@@ -179,11 +228,23 @@ public BigDecimal fakeOuterNumberSerialize(BigDecimal body) throws RestClientExc
      * 
      * Test serialization of outer string types
      * <p><b>200</b> - Output string
-     * @param body Input string as post body
+     * @param body Input string as post body (optional)
      * @return String
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public String fakeOuterStringSerialize(String body) throws RestClientException {
+        return fakeOuterStringSerializeWithHttpInfo(body).getBody();
+    }
+
+    /**
+     * 
+     * Test serialization of outer string types
+     * <p><b>200</b> - Output string
+     * @param body Input string as post body (optional)
+     * @return ResponseEntity&lt;String&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<String> fakeOuterStringSerializeWithHttpInfo(String body) throws RestClientException {
         Object postBody = body;
         
         String path = apiClient.expandPath("/fake/outer/string", Collections.<String, Object>emptyMap());
@@ -208,10 +269,22 @@ public String fakeOuterStringSerialize(String body) throws RestClientException {
      * 
      * For this test, the body for this request much reference a schema named &#x60;File&#x60;.
      * <p><b>200</b> - Success
-     * @param body The body parameter
+     * @param body  (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void testBodyWithFileSchema(FileSchemaTestClass body) throws RestClientException {
+        testBodyWithFileSchemaWithHttpInfo(body);
+    }
+
+    /**
+     * 
+     * For this test, the body for this request much reference a schema named &#x60;File&#x60;.
+     * <p><b>200</b> - Success
+     * @param body  (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> testBodyWithFileSchemaWithHttpInfo(FileSchemaTestClass body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'body' is set
@@ -235,17 +308,30 @@ public void testBodyWithFileSchema(FileSchemaTestClass body) throws RestClientEx
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.PUT, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.PUT, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * 
      * 
      * <p><b>200</b> - Success
-     * @param query The query parameter
-     * @param body The body parameter
+     * @param query  (required)
+     * @param body  (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void testBodyWithQueryParams(String query, User body) throws RestClientException {
+        testBodyWithQueryParamsWithHttpInfo(query, body);
+    }
+
+    /**
+     * 
+     * 
+     * <p><b>200</b> - Success
+     * @param query  (required)
+     * @param body  (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> testBodyWithQueryParamsWithHttpInfo(String query, User body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'query' is set
@@ -276,17 +362,29 @@ public void testBodyWithQueryParams(String query, User body) throws RestClientEx
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.PUT, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.PUT, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * To test \&quot;client\&quot; model
      * To test \&quot;client\&quot; model
      * <p><b>200</b> - successful operation
-     * @param body client model
+     * @param body client model (required)
      * @return Client
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public Client testClientModel(Client body) throws RestClientException {
+        return testClientModelWithHttpInfo(body).getBody();
+    }
+
+    /**
+     * To test \&quot;client\&quot; model
+     * To test \&quot;client\&quot; model
+     * <p><b>200</b> - successful operation
+     * @param body client model (required)
+     * @return ResponseEntity&lt;Client&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Client> testClientModelWithHttpInfo(Client body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'body' is set
@@ -319,23 +417,49 @@ public Client testClientModel(Client body) throws RestClientException {
      * Fake endpoint for testing various parameters 假端點 偽のエンドポイント 가짜 엔드 포인트 
      * <p><b>400</b> - Invalid username supplied
      * <p><b>404</b> - User not found
-     * @param number None
-     * @param _double None
-     * @param patternWithoutDelimiter None
-     * @param _byte None
-     * @param integer None
-     * @param int32 None
-     * @param int64 None
-     * @param _float None
-     * @param string None
-     * @param binary None
-     * @param date None
-     * @param dateTime None
-     * @param password None
-     * @param paramCallback None
+     * @param number None (required)
+     * @param _double None (required)
+     * @param patternWithoutDelimiter None (required)
+     * @param _byte None (required)
+     * @param integer None (optional)
+     * @param int32 None (optional)
+     * @param int64 None (optional)
+     * @param _float None (optional)
+     * @param string None (optional)
+     * @param binary None (optional)
+     * @param date None (optional)
+     * @param dateTime None (optional)
+     * @param password None (optional)
+     * @param paramCallback None (optional)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void testEndpointParameters(BigDecimal number, Double _double, String patternWithoutDelimiter, byte[] _byte, Integer integer, Integer int32, Long int64, Float _float, String string, File binary, LocalDate date, OffsetDateTime dateTime, String password, String paramCallback) throws RestClientException {
+        testEndpointParametersWithHttpInfo(number, _double, patternWithoutDelimiter, _byte, integer, int32, int64, _float, string, binary, date, dateTime, password, paramCallback);
+    }
+
+    /**
+     * Fake endpoint for testing various parameters 假端點 偽のエンドポイント 가짜 엔드 포인트 
+     * Fake endpoint for testing various parameters 假端點 偽のエンドポイント 가짜 엔드 포인트 
+     * <p><b>400</b> - Invalid username supplied
+     * <p><b>404</b> - User not found
+     * @param number None (required)
+     * @param _double None (required)
+     * @param patternWithoutDelimiter None (required)
+     * @param _byte None (required)
+     * @param integer None (optional)
+     * @param int32 None (optional)
+     * @param int64 None (optional)
+     * @param _float None (optional)
+     * @param string None (optional)
+     * @param binary None (optional)
+     * @param date None (optional)
+     * @param dateTime None (optional)
+     * @param password None (optional)
+     * @param paramCallback None (optional)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> testEndpointParametersWithHttpInfo(BigDecimal number, Double _double, String patternWithoutDelimiter, byte[] _byte, Integer integer, Integer int32, Long int64, Float _float, String string, File binary, LocalDate date, OffsetDateTime dateTime, String password, String paramCallback) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'number' is set
@@ -403,24 +527,44 @@ public void testEndpointParameters(BigDecimal number, Double _double, String pat
         String[] authNames = new String[] { "http_basic_test" };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * To test enum parameters
      * To test enum parameters
      * <p><b>400</b> - Invalid request
      * <p><b>404</b> - Not found
-     * @param enumHeaderStringArray Header parameter enum test (string array)
-     * @param enumHeaderString Header parameter enum test (string)
-     * @param enumQueryStringArray Query parameter enum test (string array)
-     * @param enumQueryString Query parameter enum test (string)
-     * @param enumQueryInteger Query parameter enum test (double)
-     * @param enumQueryDouble Query parameter enum test (double)
-     * @param enumFormStringArray Form parameter enum test (string array)
-     * @param enumFormString Form parameter enum test (string)
+     * @param enumHeaderStringArray Header parameter enum test (string array) (optional, default to new ArrayList&lt;String&gt;())
+     * @param enumHeaderString Header parameter enum test (string) (optional, default to -efg)
+     * @param enumQueryStringArray Query parameter enum test (string array) (optional, default to new ArrayList&lt;String&gt;())
+     * @param enumQueryString Query parameter enum test (string) (optional, default to -efg)
+     * @param enumQueryInteger Query parameter enum test (double) (optional)
+     * @param enumQueryDouble Query parameter enum test (double) (optional)
+     * @param enumFormStringArray Form parameter enum test (string array) (optional, default to $)
+     * @param enumFormString Form parameter enum test (string) (optional, default to -efg)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void testEnumParameters(List<String> enumHeaderStringArray, String enumHeaderString, List<String> enumQueryStringArray, String enumQueryString, Integer enumQueryInteger, Double enumQueryDouble, List<String> enumFormStringArray, String enumFormString) throws RestClientException {
+        testEnumParametersWithHttpInfo(enumHeaderStringArray, enumHeaderString, enumQueryStringArray, enumQueryString, enumQueryInteger, enumQueryDouble, enumFormStringArray, enumFormString);
+    }
+
+    /**
+     * To test enum parameters
+     * To test enum parameters
+     * <p><b>400</b> - Invalid request
+     * <p><b>404</b> - Not found
+     * @param enumHeaderStringArray Header parameter enum test (string array) (optional, default to new ArrayList&lt;String&gt;())
+     * @param enumHeaderString Header parameter enum test (string) (optional, default to -efg)
+     * @param enumQueryStringArray Query parameter enum test (string array) (optional, default to new ArrayList&lt;String&gt;())
+     * @param enumQueryString Query parameter enum test (string) (optional, default to -efg)
+     * @param enumQueryInteger Query parameter enum test (double) (optional)
+     * @param enumQueryDouble Query parameter enum test (double) (optional)
+     * @param enumFormStringArray Form parameter enum test (string array) (optional, default to $)
+     * @param enumFormString Form parameter enum test (string) (optional, default to -efg)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> testEnumParametersWithHttpInfo(List<String> enumHeaderStringArray, String enumHeaderString, List<String> enumQueryStringArray, String enumQueryString, Integer enumQueryInteger, Double enumQueryDouble, List<String> enumFormStringArray, String enumFormString) throws RestClientException {
         Object postBody = null;
         
         String path = apiClient.expandPath("/fake", Collections.<String, Object>emptyMap());
@@ -454,21 +598,38 @@ public void testEnumParameters(List<String> enumHeaderStringArray, String enumHe
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.GET, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.GET, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * Fake endpoint to test group parameters (optional)
      * Fake endpoint to test group parameters (optional)
      * <p><b>400</b> - Someting wrong
-     * @param requiredStringGroup Required String in group parameters
-     * @param requiredBooleanGroup Required Boolean in group parameters
-     * @param requiredInt64Group Required Integer in group parameters
-     * @param stringGroup String in group parameters
-     * @param booleanGroup Boolean in group parameters
-     * @param int64Group Integer in group parameters
+     * @param requiredStringGroup Required String in group parameters (required)
+     * @param requiredBooleanGroup Required Boolean in group parameters (required)
+     * @param requiredInt64Group Required Integer in group parameters (required)
+     * @param stringGroup String in group parameters (optional)
+     * @param booleanGroup Boolean in group parameters (optional)
+     * @param int64Group Integer in group parameters (optional)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void testGroupParameters(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws RestClientException {
+        testGroupParametersWithHttpInfo(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
+    }
+
+    /**
+     * Fake endpoint to test group parameters (optional)
+     * Fake endpoint to test group parameters (optional)
+     * <p><b>400</b> - Someting wrong
+     * @param requiredStringGroup Required String in group parameters (required)
+     * @param requiredBooleanGroup Required Boolean in group parameters (required)
+     * @param requiredInt64Group Required Integer in group parameters (required)
+     * @param stringGroup String in group parameters (optional)
+     * @param booleanGroup Boolean in group parameters (optional)
+     * @param int64Group Integer in group parameters (optional)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> testGroupParametersWithHttpInfo(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'requiredStringGroup' is set
@@ -510,16 +671,28 @@ public void testGroupParameters(Integer requiredStringGroup, Boolean requiredBoo
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.DELETE, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.DELETE, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * test inline additionalProperties
      * 
      * <p><b>200</b> - successful operation
-     * @param param request body
+     * @param param request body (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void testInlineAdditionalProperties(Map<String, String> param) throws RestClientException {
+        testInlineAdditionalPropertiesWithHttpInfo(param);
+    }
+
+    /**
+     * test inline additionalProperties
+     * 
+     * <p><b>200</b> - successful operation
+     * @param param request body (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> testInlineAdditionalPropertiesWithHttpInfo(Map<String, String> param) throws RestClientException {
         Object postBody = param;
         
         // verify the required parameter 'param' is set
@@ -543,17 +716,30 @@ public void testInlineAdditionalProperties(Map<String, String> param) throws Res
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * test json serialization of form data
      * 
      * <p><b>200</b> - successful operation
-     * @param param field1
-     * @param param2 field2
+     * @param param field1 (required)
+     * @param param2 field2 (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void testJsonFormData(String param, String param2) throws RestClientException {
+        testJsonFormDataWithHttpInfo(param, param2);
+    }
+
+    /**
+     * test json serialization of form data
+     * 
+     * <p><b>200</b> - successful operation
+     * @param param field1 (required)
+     * @param param2 field2 (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> testJsonFormDataWithHttpInfo(String param, String param2) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'param' is set
@@ -587,20 +773,36 @@ public void testJsonFormData(String param, String param2) throws RestClientExcep
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.GET, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.GET, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * 
      * To test the collection format in query parameters
      * <p><b>200</b> - Success
-     * @param pipe The pipe parameter
-     * @param ioutil The ioutil parameter
-     * @param http The http parameter
-     * @param url The url parameter
-     * @param context The context parameter
+     * @param pipe  (required)
+     * @param ioutil  (required)
+     * @param http  (required)
+     * @param url  (required)
+     * @param context  (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void testQueryParameterCollectionFormat(List<String> pipe, List<String> ioutil, List<String> http, List<String> url, List<String> context) throws RestClientException {
+        testQueryParameterCollectionFormatWithHttpInfo(pipe, ioutil, http, url, context);
+    }
+
+    /**
+     * 
+     * To test the collection format in query parameters
+     * <p><b>200</b> - Success
+     * @param pipe  (required)
+     * @param ioutil  (required)
+     * @param http  (required)
+     * @param url  (required)
+     * @param context  (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> testQueryParameterCollectionFormatWithHttpInfo(List<String> pipe, List<String> ioutil, List<String> http, List<String> url, List<String> context) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'pipe' is set
@@ -648,6 +850,6 @@ public void testQueryParameterCollectionFormat(List<String> pipe, List<String> i
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.PUT, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.PUT, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
 }
diff --git a/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java b/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
index b619b51c261c..74d86633d8bb 100644
--- a/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
+++ b/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
@@ -24,6 +24,7 @@
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
 
 
 @Component("org.openapitools.client.api.FakeClassnameTags123Api")
@@ -51,11 +52,23 @@ public void setApiClient(ApiClient apiClient) {
      * To test class name in snake case
      * To test class name in snake case
      * <p><b>200</b> - successful operation
-     * @param body client model
+     * @param body client model (required)
      * @return Client
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public Client testClassname(Client body) throws RestClientException {
+        return testClassnameWithHttpInfo(body).getBody();
+    }
+
+    /**
+     * To test class name in snake case
+     * To test class name in snake case
+     * <p><b>200</b> - successful operation
+     * @param body client model (required)
+     * @return ResponseEntity&lt;Client&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Client> testClassnameWithHttpInfo(Client body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'body' is set
diff --git a/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/PetApi.java b/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/PetApi.java
index d012578f0fad..31c2f785a289 100644
--- a/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/PetApi.java
+++ b/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/PetApi.java
@@ -26,6 +26,7 @@
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
 
 
 @Component("org.openapitools.client.api.PetApi")
@@ -54,10 +55,23 @@ public void setApiClient(ApiClient apiClient) {
      * 
      * <p><b>200</b> - successful operation
      * <p><b>405</b> - Invalid input
-     * @param body Pet object that needs to be added to the store
+     * @param body Pet object that needs to be added to the store (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void addPet(Pet body) throws RestClientException {
+        addPetWithHttpInfo(body);
+    }
+
+    /**
+     * Add a new pet to the store
+     * 
+     * <p><b>200</b> - successful operation
+     * <p><b>405</b> - Invalid input
+     * @param body Pet object that needs to be added to the store (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> addPetWithHttpInfo(Pet body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'body' is set
@@ -81,18 +95,32 @@ public void addPet(Pet body) throws RestClientException {
         String[] authNames = new String[] { "petstore_auth" };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * Deletes a pet
      * 
      * <p><b>200</b> - successful operation
      * <p><b>400</b> - Invalid pet value
-     * @param petId Pet id to delete
-     * @param apiKey The apiKey parameter
+     * @param petId Pet id to delete (required)
+     * @param apiKey  (optional)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void deletePet(Long petId, String apiKey) throws RestClientException {
+        deletePetWithHttpInfo(petId, apiKey);
+    }
+
+    /**
+     * Deletes a pet
+     * 
+     * <p><b>200</b> - successful operation
+     * <p><b>400</b> - Invalid pet value
+     * @param petId Pet id to delete (required)
+     * @param apiKey  (optional)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> deletePetWithHttpInfo(Long petId, String apiKey) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'petId' is set
@@ -120,18 +148,31 @@ public void deletePet(Long petId, String apiKey) throws RestClientException {
         String[] authNames = new String[] { "petstore_auth" };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.DELETE, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.DELETE, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * Finds Pets by status
      * Multiple status values can be provided with comma separated strings
      * <p><b>200</b> - successful operation
      * <p><b>400</b> - Invalid status value
-     * @param status Status values that need to be considered for filter
+     * @param status Status values that need to be considered for filter (required)
      * @return List&lt;Pet&gt;
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public List<Pet> findPetsByStatus(List<String> status) throws RestClientException {
+        return findPetsByStatusWithHttpInfo(status).getBody();
+    }
+
+    /**
+     * Finds Pets by status
+     * Multiple status values can be provided with comma separated strings
+     * <p><b>200</b> - successful operation
+     * <p><b>400</b> - Invalid status value
+     * @param status Status values that need to be considered for filter (required)
+     * @return ResponseEntity&lt;List&lt;Pet&gt;&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<List<Pet>> findPetsByStatusWithHttpInfo(List<String> status) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'status' is set
@@ -164,11 +205,26 @@ public List<Pet> findPetsByStatus(List<String> status) throws RestClientExceptio
      * Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
      * <p><b>200</b> - successful operation
      * <p><b>400</b> - Invalid tag value
-     * @param tags Tags to filter by
+     * @param tags Tags to filter by (required)
      * @return List&lt;Pet&gt;
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
+    @Deprecated
     public List<Pet> findPetsByTags(List<String> tags) throws RestClientException {
+        return findPetsByTagsWithHttpInfo(tags).getBody();
+    }
+
+    /**
+     * Finds Pets by tags
+     * Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
+     * <p><b>200</b> - successful operation
+     * <p><b>400</b> - Invalid tag value
+     * @param tags Tags to filter by (required)
+     * @return ResponseEntity&lt;List&lt;Pet&gt;&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    @Deprecated
+    public ResponseEntity<List<Pet>> findPetsByTagsWithHttpInfo(List<String> tags) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'tags' is set
@@ -202,11 +258,25 @@ public List<Pet> findPetsByTags(List<String> tags) throws RestClientException {
      * <p><b>200</b> - successful operation
      * <p><b>400</b> - Invalid ID supplied
      * <p><b>404</b> - Pet not found
-     * @param petId ID of pet to return
+     * @param petId ID of pet to return (required)
      * @return Pet
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public Pet getPetById(Long petId) throws RestClientException {
+        return getPetByIdWithHttpInfo(petId).getBody();
+    }
+
+    /**
+     * Find pet by ID
+     * Returns a single pet
+     * <p><b>200</b> - successful operation
+     * <p><b>400</b> - Invalid ID supplied
+     * <p><b>404</b> - Pet not found
+     * @param petId ID of pet to return (required)
+     * @return ResponseEntity&lt;Pet&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Pet> getPetByIdWithHttpInfo(Long petId) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'petId' is set
@@ -242,10 +312,25 @@ public Pet getPetById(Long petId) throws RestClientException {
      * <p><b>400</b> - Invalid ID supplied
      * <p><b>404</b> - Pet not found
      * <p><b>405</b> - Validation exception
-     * @param body Pet object that needs to be added to the store
+     * @param body Pet object that needs to be added to the store (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void updatePet(Pet body) throws RestClientException {
+        updatePetWithHttpInfo(body);
+    }
+
+    /**
+     * Update an existing pet
+     * 
+     * <p><b>200</b> - successful operation
+     * <p><b>400</b> - Invalid ID supplied
+     * <p><b>404</b> - Pet not found
+     * <p><b>405</b> - Validation exception
+     * @param body Pet object that needs to be added to the store (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> updatePetWithHttpInfo(Pet body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'body' is set
@@ -269,18 +354,32 @@ public void updatePet(Pet body) throws RestClientException {
         String[] authNames = new String[] { "petstore_auth" };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.PUT, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.PUT, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * Updates a pet in the store with form data
      * 
      * <p><b>405</b> - Invalid input
-     * @param petId ID of pet that needs to be updated
-     * @param name Updated name of the pet
-     * @param status Updated status of the pet
+     * @param petId ID of pet that needs to be updated (required)
+     * @param name Updated name of the pet (optional)
+     * @param status Updated status of the pet (optional)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void updatePetWithForm(Long petId, String name, String status) throws RestClientException {
+        updatePetWithFormWithHttpInfo(petId, name, status);
+    }
+
+    /**
+     * Updates a pet in the store with form data
+     * 
+     * <p><b>405</b> - Invalid input
+     * @param petId ID of pet that needs to be updated (required)
+     * @param name Updated name of the pet (optional)
+     * @param status Updated status of the pet (optional)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> updatePetWithFormWithHttpInfo(Long petId, String name, String status) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'petId' is set
@@ -312,19 +411,33 @@ public void updatePetWithForm(Long petId, String name, String status) throws Res
         String[] authNames = new String[] { "petstore_auth" };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * uploads an image
      * 
      * <p><b>200</b> - successful operation
-     * @param petId ID of pet to update
-     * @param additionalMetadata Additional data to pass to server
-     * @param file file to upload
+     * @param petId ID of pet to update (required)
+     * @param additionalMetadata Additional data to pass to server (optional)
+     * @param file file to upload (optional)
      * @return ModelApiResponse
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public ModelApiResponse uploadFile(Long petId, String additionalMetadata, File file) throws RestClientException {
+        return uploadFileWithHttpInfo(petId, additionalMetadata, file).getBody();
+    }
+
+    /**
+     * uploads an image
+     * 
+     * <p><b>200</b> - successful operation
+     * @param petId ID of pet to update (required)
+     * @param additionalMetadata Additional data to pass to server (optional)
+     * @param file file to upload (optional)
+     * @return ResponseEntity&lt;ModelApiResponse&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<ModelApiResponse> uploadFileWithHttpInfo(Long petId, String additionalMetadata, File file) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'petId' is set
@@ -364,13 +477,27 @@ public ModelApiResponse uploadFile(Long petId, String additionalMetadata, File f
      * uploads an image (required)
      * 
      * <p><b>200</b> - successful operation
-     * @param petId ID of pet to update
-     * @param requiredFile file to upload
-     * @param additionalMetadata Additional data to pass to server
+     * @param petId ID of pet to update (required)
+     * @param requiredFile file to upload (required)
+     * @param additionalMetadata Additional data to pass to server (optional)
      * @return ModelApiResponse
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public ModelApiResponse uploadFileWithRequiredFile(Long petId, File requiredFile, String additionalMetadata) throws RestClientException {
+        return uploadFileWithRequiredFileWithHttpInfo(petId, requiredFile, additionalMetadata).getBody();
+    }
+
+    /**
+     * uploads an image (required)
+     * 
+     * <p><b>200</b> - successful operation
+     * @param petId ID of pet to update (required)
+     * @param requiredFile file to upload (required)
+     * @param additionalMetadata Additional data to pass to server (optional)
+     * @return ResponseEntity&lt;ModelApiResponse&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<ModelApiResponse> uploadFileWithRequiredFileWithHttpInfo(Long petId, File requiredFile, String additionalMetadata) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'petId' is set
diff --git a/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/StoreApi.java b/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/StoreApi.java
index 4488bd0ae0a4..29b990a85d1d 100644
--- a/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/StoreApi.java
+++ b/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/StoreApi.java
@@ -24,6 +24,7 @@
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
 
 
 @Component("org.openapitools.client.api.StoreApi")
@@ -52,10 +53,23 @@ public void setApiClient(ApiClient apiClient) {
      * For valid response try integer IDs with value &lt; 1000. Anything above 1000 or nonintegers will generate API errors
      * <p><b>400</b> - Invalid ID supplied
      * <p><b>404</b> - Order not found
-     * @param orderId ID of the order that needs to be deleted
+     * @param orderId ID of the order that needs to be deleted (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void deleteOrder(String orderId) throws RestClientException {
+        deleteOrderWithHttpInfo(orderId);
+    }
+
+    /**
+     * Delete purchase order by ID
+     * For valid response try integer IDs with value &lt; 1000. Anything above 1000 or nonintegers will generate API errors
+     * <p><b>400</b> - Invalid ID supplied
+     * <p><b>404</b> - Order not found
+     * @param orderId ID of the order that needs to be deleted (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> deleteOrderWithHttpInfo(String orderId) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'orderId' is set
@@ -80,7 +94,7 @@ public void deleteOrder(String orderId) throws RestClientException {
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.DELETE, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.DELETE, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * Returns pet inventories by status
@@ -90,6 +104,17 @@ public void deleteOrder(String orderId) throws RestClientException {
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public Map<String, Integer> getInventory() throws RestClientException {
+        return getInventoryWithHttpInfo().getBody();
+    }
+
+    /**
+     * Returns pet inventories by status
+     * Returns a map of status codes to quantities
+     * <p><b>200</b> - successful operation
+     * @return ResponseEntity&lt;Map&lt;String, Integer&gt;&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Map<String, Integer>> getInventoryWithHttpInfo() throws RestClientException {
         Object postBody = null;
         
         String path = apiClient.expandPath("/store/inventory", Collections.<String, Object>emptyMap());
@@ -116,11 +141,25 @@ public Map<String, Integer> getInventory() throws RestClientException {
      * <p><b>200</b> - successful operation
      * <p><b>400</b> - Invalid ID supplied
      * <p><b>404</b> - Order not found
-     * @param orderId ID of pet that needs to be fetched
+     * @param orderId ID of pet that needs to be fetched (required)
      * @return Order
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public Order getOrderById(Long orderId) throws RestClientException {
+        return getOrderByIdWithHttpInfo(orderId).getBody();
+    }
+
+    /**
+     * Find purchase order by ID
+     * For valid response try integer IDs with value &lt;&#x3D; 5 or &gt; 10. Other values will generated exceptions
+     * <p><b>200</b> - successful operation
+     * <p><b>400</b> - Invalid ID supplied
+     * <p><b>404</b> - Order not found
+     * @param orderId ID of pet that needs to be fetched (required)
+     * @return ResponseEntity&lt;Order&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Order> getOrderByIdWithHttpInfo(Long orderId) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'orderId' is set
@@ -154,11 +193,24 @@ public Order getOrderById(Long orderId) throws RestClientException {
      * 
      * <p><b>200</b> - successful operation
      * <p><b>400</b> - Invalid Order
-     * @param body order placed for purchasing the pet
+     * @param body order placed for purchasing the pet (required)
      * @return Order
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public Order placeOrder(Order body) throws RestClientException {
+        return placeOrderWithHttpInfo(body).getBody();
+    }
+
+    /**
+     * Place an order for a pet
+     * 
+     * <p><b>200</b> - successful operation
+     * <p><b>400</b> - Invalid Order
+     * @param body order placed for purchasing the pet (required)
+     * @return ResponseEntity&lt;Order&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Order> placeOrderWithHttpInfo(Order body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'body' is set
diff --git a/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/UserApi.java b/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/UserApi.java
index 1d2d59616b6d..66db8e8cd145 100644
--- a/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/UserApi.java
+++ b/samples/client/petstore/java/resttemplate-withXml/src/main/java/org/openapitools/client/api/UserApi.java
@@ -24,6 +24,7 @@
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
 
 
 @Component("org.openapitools.client.api.UserApi")
@@ -51,10 +52,22 @@ public void setApiClient(ApiClient apiClient) {
      * Create user
      * This can only be done by the logged in user.
      * <p><b>0</b> - successful operation
-     * @param body Created user object
+     * @param body Created user object (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void createUser(User body) throws RestClientException {
+        createUserWithHttpInfo(body);
+    }
+
+    /**
+     * Create user
+     * This can only be done by the logged in user.
+     * <p><b>0</b> - successful operation
+     * @param body Created user object (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> createUserWithHttpInfo(User body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'body' is set
@@ -76,16 +89,28 @@ public void createUser(User body) throws RestClientException {
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * Creates list of users with given input array
      * 
      * <p><b>0</b> - successful operation
-     * @param body List of user object
+     * @param body List of user object (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void createUsersWithArrayInput(List<User> body) throws RestClientException {
+        createUsersWithArrayInputWithHttpInfo(body);
+    }
+
+    /**
+     * Creates list of users with given input array
+     * 
+     * <p><b>0</b> - successful operation
+     * @param body List of user object (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> createUsersWithArrayInputWithHttpInfo(List<User> body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'body' is set
@@ -107,16 +132,28 @@ public void createUsersWithArrayInput(List<User> body) throws RestClientExceptio
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * Creates list of users with given input array
      * 
      * <p><b>0</b> - successful operation
-     * @param body List of user object
+     * @param body List of user object (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void createUsersWithListInput(List<User> body) throws RestClientException {
+        createUsersWithListInputWithHttpInfo(body);
+    }
+
+    /**
+     * Creates list of users with given input array
+     * 
+     * <p><b>0</b> - successful operation
+     * @param body List of user object (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> createUsersWithListInputWithHttpInfo(List<User> body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'body' is set
@@ -138,17 +175,30 @@ public void createUsersWithListInput(List<User> body) throws RestClientException
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * Delete user
      * This can only be done by the logged in user.
      * <p><b>400</b> - Invalid username supplied
      * <p><b>404</b> - User not found
-     * @param username The name that needs to be deleted
+     * @param username The name that needs to be deleted (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void deleteUser(String username) throws RestClientException {
+        deleteUserWithHttpInfo(username);
+    }
+
+    /**
+     * Delete user
+     * This can only be done by the logged in user.
+     * <p><b>400</b> - Invalid username supplied
+     * <p><b>404</b> - User not found
+     * @param username The name that needs to be deleted (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> deleteUserWithHttpInfo(String username) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'username' is set
@@ -173,7 +223,7 @@ public void deleteUser(String username) throws RestClientException {
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.DELETE, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.DELETE, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * Get user by user name
@@ -181,11 +231,25 @@ public void deleteUser(String username) throws RestClientException {
      * <p><b>200</b> - successful operation
      * <p><b>400</b> - Invalid username supplied
      * <p><b>404</b> - User not found
-     * @param username The name that needs to be fetched. Use user1 for testing.
+     * @param username The name that needs to be fetched. Use user1 for testing. (required)
      * @return User
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public User getUserByName(String username) throws RestClientException {
+        return getUserByNameWithHttpInfo(username).getBody();
+    }
+
+    /**
+     * Get user by user name
+     * 
+     * <p><b>200</b> - successful operation
+     * <p><b>400</b> - Invalid username supplied
+     * <p><b>404</b> - User not found
+     * @param username The name that needs to be fetched. Use user1 for testing. (required)
+     * @return ResponseEntity&lt;User&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<User> getUserByNameWithHttpInfo(String username) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'username' is set
@@ -219,12 +283,26 @@ public User getUserByName(String username) throws RestClientException {
      * 
      * <p><b>200</b> - successful operation
      * <p><b>400</b> - Invalid username/password supplied
-     * @param username The user name for login
-     * @param password The password for login in clear text
+     * @param username The user name for login (required)
+     * @param password The password for login in clear text (required)
      * @return String
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public String loginUser(String username, String password) throws RestClientException {
+        return loginUserWithHttpInfo(username, password).getBody();
+    }
+
+    /**
+     * Logs user into the system
+     * 
+     * <p><b>200</b> - successful operation
+     * <p><b>400</b> - Invalid username/password supplied
+     * @param username The user name for login (required)
+     * @param password The password for login in clear text (required)
+     * @return ResponseEntity&lt;String&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<String> loginUserWithHttpInfo(String username, String password) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'username' is set
@@ -265,6 +343,17 @@ public String loginUser(String username, String password) throws RestClientExcep
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void logoutUser() throws RestClientException {
+        logoutUserWithHttpInfo();
+    }
+
+    /**
+     * Logs out current logged in user session
+     * 
+     * <p><b>0</b> - successful operation
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> logoutUserWithHttpInfo() throws RestClientException {
         Object postBody = null;
         
         String path = apiClient.expandPath("/user/logout", Collections.<String, Object>emptyMap());
@@ -281,18 +370,32 @@ public void logoutUser() throws RestClientException {
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.GET, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.GET, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * Updated user
      * This can only be done by the logged in user.
      * <p><b>400</b> - Invalid user supplied
      * <p><b>404</b> - User not found
-     * @param username name that need to be deleted
-     * @param body Updated user object
+     * @param username name that need to be deleted (required)
+     * @param body Updated user object (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void updateUser(String username, User body) throws RestClientException {
+        updateUserWithHttpInfo(username, body);
+    }
+
+    /**
+     * Updated user
+     * This can only be done by the logged in user.
+     * <p><b>400</b> - Invalid user supplied
+     * <p><b>404</b> - User not found
+     * @param username name that need to be deleted (required)
+     * @param body Updated user object (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> updateUserWithHttpInfo(String username, User body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'username' is set
@@ -322,6 +425,6 @@ public void updateUser(String username, User body) throws RestClientException {
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.PUT, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.PUT, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
 }
diff --git a/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/ApiClient.java
index 264ea075d190..5915c3dc6660 100644
--- a/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/ApiClient.java
@@ -86,9 +86,6 @@ private String collectionToString(Collection<? extends CharSequence> collection)
 
     private Map<String, Authentication> authentications;
 
-    private HttpStatus statusCode;
-    private MultiValueMap<String, String> responseHeaders;
-
     private DateFormat dateFormat;
 
     public ApiClient() {
@@ -141,22 +138,6 @@ public ApiClient setBasePath(String basePath) {
         return this;
     }
 
-    /**
-     * Gets the status code of the previous request
-     * @return HttpStatus the status code
-     */
-    public HttpStatus getStatusCode() {
-        return statusCode;
-    }
-
-    /**
-     * Gets the response headers of the previous request
-     * @return MultiValueMap a map of response headers
-     */
-    public MultiValueMap<String, String> getResponseHeaders() {
-        return responseHeaders;
-    }
-
     /**
      * Get authentications (key: authentication name, value: authentication).
      * @return Map the currently configured authentication types
@@ -563,9 +544,9 @@ public String expandPath(String pathTemplate, Map<String, Object> variables) {
      * @param contentType The request's Content-Type header
      * @param authNames The authentications to apply
      * @param returnType The return type into which to deserialize the response
-     * @return The response body in chosen type
+     * @return ResponseEntity&lt;T&gt; The response of the chosen type
      */
-    public <T> T invokeAPI(String path, HttpMethod method, MultiValueMap<String, String> queryParams, Object body, HttpHeaders headerParams, MultiValueMap<String, Object> formParams, List<MediaType> accept, MediaType contentType, String[] authNames, ParameterizedTypeReference<T> returnType) throws RestClientException {
+    public <T> ResponseEntity<T> invokeAPI(String path, HttpMethod method, MultiValueMap<String, String> queryParams, Object body, HttpHeaders headerParams, MultiValueMap<String, Object> formParams, List<MediaType> accept, MediaType contentType, String[] authNames, ParameterizedTypeReference<T> returnType) throws RestClientException {
         updateParamsForAuth(authNames, queryParams, headerParams);
 
         final UriComponentsBuilder builder = UriComponentsBuilder.fromHttpUrl(basePath).path(path);
@@ -607,16 +588,11 @@ public <T> T invokeAPI(String path, HttpMethod method, MultiValueMap<String, Str
 
         ResponseEntity<T> responseEntity = restTemplate.exchange(requestEntity, returnType);
 
-        statusCode = responseEntity.getStatusCode();
-        responseHeaders = responseEntity.getHeaders();
-
-        if (responseEntity.getStatusCode() == HttpStatus.NO_CONTENT) {
-            return null;
-        } else if (responseEntity.getStatusCode().is2xxSuccessful()) {
-            return responseEntity.getBody();
+        if (responseEntity.getStatusCode().is2xxSuccessful()) {
+            return responseEntity;
         } else {
             // The error handler built into the RestTemplate should handle 400 and 500 series errors.
-            throw new RestClientException("API returned " + statusCode + " and it wasn't handled by the RestTemplate error handler");
+            throw new RestClientException("API returned " + responseEntity.getStatusCode() + " and it wasn't handled by the RestTemplate error handler");
         }
     }
 
diff --git a/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/AnotherFakeApi.java b/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
index ffb5afa7d047..542171d1d507 100644
--- a/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
+++ b/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
@@ -24,6 +24,7 @@
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
 
 
 @Component("org.openapitools.client.api.AnotherFakeApi")
@@ -51,11 +52,23 @@ public void setApiClient(ApiClient apiClient) {
      * To test special tags
      * To test special tags and operation ID starting with number
      * <p><b>200</b> - successful operation
-     * @param body client model
+     * @param body client model (required)
      * @return Client
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public Client call123testSpecialTags(Client body) throws RestClientException {
+        return call123testSpecialTagsWithHttpInfo(body).getBody();
+    }
+
+    /**
+     * To test special tags
+     * To test special tags and operation ID starting with number
+     * <p><b>200</b> - successful operation
+     * @param body client model (required)
+     * @return ResponseEntity&lt;Client&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Client> call123testSpecialTagsWithHttpInfo(Client body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'body' is set
diff --git a/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/FakeApi.java
index 8b7f1118e5f7..73d0e62ffaa3 100644
--- a/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -32,6 +32,7 @@
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
 
 
 @Component("org.openapitools.client.api.FakeApi")
@@ -59,10 +60,22 @@ public void setApiClient(ApiClient apiClient) {
      * creates an XmlItem
      * this route creates an XmlItem
      * <p><b>200</b> - successful operation
-     * @param xmlItem XmlItem Body
+     * @param xmlItem XmlItem Body (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void createXmlItem(XmlItem xmlItem) throws RestClientException {
+        createXmlItemWithHttpInfo(xmlItem);
+    }
+
+    /**
+     * creates an XmlItem
+     * this route creates an XmlItem
+     * <p><b>200</b> - successful operation
+     * @param xmlItem XmlItem Body (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> createXmlItemWithHttpInfo(XmlItem xmlItem) throws RestClientException {
         Object postBody = xmlItem;
         
         // verify the required parameter 'xmlItem' is set
@@ -86,17 +99,29 @@ public void createXmlItem(XmlItem xmlItem) throws RestClientException {
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * 
      * Test serialization of outer boolean types
      * <p><b>200</b> - Output boolean
-     * @param body Input boolean as post body
+     * @param body Input boolean as post body (optional)
      * @return Boolean
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public Boolean fakeOuterBooleanSerialize(Boolean body) throws RestClientException {
+        return fakeOuterBooleanSerializeWithHttpInfo(body).getBody();
+    }
+
+    /**
+     * 
+     * Test serialization of outer boolean types
+     * <p><b>200</b> - Output boolean
+     * @param body Input boolean as post body (optional)
+     * @return ResponseEntity&lt;Boolean&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Boolean> fakeOuterBooleanSerializeWithHttpInfo(Boolean body) throws RestClientException {
         Object postBody = body;
         
         String path = apiClient.expandPath("/fake/outer/boolean", Collections.<String, Object>emptyMap());
@@ -121,11 +146,23 @@ public Boolean fakeOuterBooleanSerialize(Boolean body) throws RestClientExceptio
      * 
      * Test serialization of object with outer number type
      * <p><b>200</b> - Output composite
-     * @param body Input composite as post body
+     * @param body Input composite as post body (optional)
      * @return OuterComposite
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public OuterComposite fakeOuterCompositeSerialize(OuterComposite body) throws RestClientException {
+        return fakeOuterCompositeSerializeWithHttpInfo(body).getBody();
+    }
+
+    /**
+     * 
+     * Test serialization of object with outer number type
+     * <p><b>200</b> - Output composite
+     * @param body Input composite as post body (optional)
+     * @return ResponseEntity&lt;OuterComposite&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<OuterComposite> fakeOuterCompositeSerializeWithHttpInfo(OuterComposite body) throws RestClientException {
         Object postBody = body;
         
         String path = apiClient.expandPath("/fake/outer/composite", Collections.<String, Object>emptyMap());
@@ -150,11 +187,23 @@ public OuterComposite fakeOuterCompositeSerialize(OuterComposite body) throws Re
      * 
      * Test serialization of outer number types
      * <p><b>200</b> - Output number
-     * @param body Input number as post body
+     * @param body Input number as post body (optional)
      * @return BigDecimal
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public BigDecimal fakeOuterNumberSerialize(BigDecimal body) throws RestClientException {
+        return fakeOuterNumberSerializeWithHttpInfo(body).getBody();
+    }
+
+    /**
+     * 
+     * Test serialization of outer number types
+     * <p><b>200</b> - Output number
+     * @param body Input number as post body (optional)
+     * @return ResponseEntity&lt;BigDecimal&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<BigDecimal> fakeOuterNumberSerializeWithHttpInfo(BigDecimal body) throws RestClientException {
         Object postBody = body;
         
         String path = apiClient.expandPath("/fake/outer/number", Collections.<String, Object>emptyMap());
@@ -179,11 +228,23 @@ public BigDecimal fakeOuterNumberSerialize(BigDecimal body) throws RestClientExc
      * 
      * Test serialization of outer string types
      * <p><b>200</b> - Output string
-     * @param body Input string as post body
+     * @param body Input string as post body (optional)
      * @return String
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public String fakeOuterStringSerialize(String body) throws RestClientException {
+        return fakeOuterStringSerializeWithHttpInfo(body).getBody();
+    }
+
+    /**
+     * 
+     * Test serialization of outer string types
+     * <p><b>200</b> - Output string
+     * @param body Input string as post body (optional)
+     * @return ResponseEntity&lt;String&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<String> fakeOuterStringSerializeWithHttpInfo(String body) throws RestClientException {
         Object postBody = body;
         
         String path = apiClient.expandPath("/fake/outer/string", Collections.<String, Object>emptyMap());
@@ -208,10 +269,22 @@ public String fakeOuterStringSerialize(String body) throws RestClientException {
      * 
      * For this test, the body for this request much reference a schema named &#x60;File&#x60;.
      * <p><b>200</b> - Success
-     * @param body The body parameter
+     * @param body  (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void testBodyWithFileSchema(FileSchemaTestClass body) throws RestClientException {
+        testBodyWithFileSchemaWithHttpInfo(body);
+    }
+
+    /**
+     * 
+     * For this test, the body for this request much reference a schema named &#x60;File&#x60;.
+     * <p><b>200</b> - Success
+     * @param body  (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> testBodyWithFileSchemaWithHttpInfo(FileSchemaTestClass body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'body' is set
@@ -235,17 +308,30 @@ public void testBodyWithFileSchema(FileSchemaTestClass body) throws RestClientEx
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.PUT, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.PUT, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * 
      * 
      * <p><b>200</b> - Success
-     * @param query The query parameter
-     * @param body The body parameter
+     * @param query  (required)
+     * @param body  (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void testBodyWithQueryParams(String query, User body) throws RestClientException {
+        testBodyWithQueryParamsWithHttpInfo(query, body);
+    }
+
+    /**
+     * 
+     * 
+     * <p><b>200</b> - Success
+     * @param query  (required)
+     * @param body  (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> testBodyWithQueryParamsWithHttpInfo(String query, User body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'query' is set
@@ -276,17 +362,29 @@ public void testBodyWithQueryParams(String query, User body) throws RestClientEx
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.PUT, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.PUT, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * To test \&quot;client\&quot; model
      * To test \&quot;client\&quot; model
      * <p><b>200</b> - successful operation
-     * @param body client model
+     * @param body client model (required)
      * @return Client
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public Client testClientModel(Client body) throws RestClientException {
+        return testClientModelWithHttpInfo(body).getBody();
+    }
+
+    /**
+     * To test \&quot;client\&quot; model
+     * To test \&quot;client\&quot; model
+     * <p><b>200</b> - successful operation
+     * @param body client model (required)
+     * @return ResponseEntity&lt;Client&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Client> testClientModelWithHttpInfo(Client body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'body' is set
@@ -319,23 +417,49 @@ public Client testClientModel(Client body) throws RestClientException {
      * Fake endpoint for testing various parameters 假端點 偽のエンドポイント 가짜 엔드 포인트 
      * <p><b>400</b> - Invalid username supplied
      * <p><b>404</b> - User not found
-     * @param number None
-     * @param _double None
-     * @param patternWithoutDelimiter None
-     * @param _byte None
-     * @param integer None
-     * @param int32 None
-     * @param int64 None
-     * @param _float None
-     * @param string None
-     * @param binary None
-     * @param date None
-     * @param dateTime None
-     * @param password None
-     * @param paramCallback None
+     * @param number None (required)
+     * @param _double None (required)
+     * @param patternWithoutDelimiter None (required)
+     * @param _byte None (required)
+     * @param integer None (optional)
+     * @param int32 None (optional)
+     * @param int64 None (optional)
+     * @param _float None (optional)
+     * @param string None (optional)
+     * @param binary None (optional)
+     * @param date None (optional)
+     * @param dateTime None (optional)
+     * @param password None (optional)
+     * @param paramCallback None (optional)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void testEndpointParameters(BigDecimal number, Double _double, String patternWithoutDelimiter, byte[] _byte, Integer integer, Integer int32, Long int64, Float _float, String string, File binary, LocalDate date, OffsetDateTime dateTime, String password, String paramCallback) throws RestClientException {
+        testEndpointParametersWithHttpInfo(number, _double, patternWithoutDelimiter, _byte, integer, int32, int64, _float, string, binary, date, dateTime, password, paramCallback);
+    }
+
+    /**
+     * Fake endpoint for testing various parameters 假端點 偽のエンドポイント 가짜 엔드 포인트 
+     * Fake endpoint for testing various parameters 假端點 偽のエンドポイント 가짜 엔드 포인트 
+     * <p><b>400</b> - Invalid username supplied
+     * <p><b>404</b> - User not found
+     * @param number None (required)
+     * @param _double None (required)
+     * @param patternWithoutDelimiter None (required)
+     * @param _byte None (required)
+     * @param integer None (optional)
+     * @param int32 None (optional)
+     * @param int64 None (optional)
+     * @param _float None (optional)
+     * @param string None (optional)
+     * @param binary None (optional)
+     * @param date None (optional)
+     * @param dateTime None (optional)
+     * @param password None (optional)
+     * @param paramCallback None (optional)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> testEndpointParametersWithHttpInfo(BigDecimal number, Double _double, String patternWithoutDelimiter, byte[] _byte, Integer integer, Integer int32, Long int64, Float _float, String string, File binary, LocalDate date, OffsetDateTime dateTime, String password, String paramCallback) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'number' is set
@@ -403,24 +527,44 @@ public void testEndpointParameters(BigDecimal number, Double _double, String pat
         String[] authNames = new String[] { "http_basic_test" };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * To test enum parameters
      * To test enum parameters
      * <p><b>400</b> - Invalid request
      * <p><b>404</b> - Not found
-     * @param enumHeaderStringArray Header parameter enum test (string array)
-     * @param enumHeaderString Header parameter enum test (string)
-     * @param enumQueryStringArray Query parameter enum test (string array)
-     * @param enumQueryString Query parameter enum test (string)
-     * @param enumQueryInteger Query parameter enum test (double)
-     * @param enumQueryDouble Query parameter enum test (double)
-     * @param enumFormStringArray Form parameter enum test (string array)
-     * @param enumFormString Form parameter enum test (string)
+     * @param enumHeaderStringArray Header parameter enum test (string array) (optional, default to new ArrayList&lt;String&gt;())
+     * @param enumHeaderString Header parameter enum test (string) (optional, default to -efg)
+     * @param enumQueryStringArray Query parameter enum test (string array) (optional, default to new ArrayList&lt;String&gt;())
+     * @param enumQueryString Query parameter enum test (string) (optional, default to -efg)
+     * @param enumQueryInteger Query parameter enum test (double) (optional)
+     * @param enumQueryDouble Query parameter enum test (double) (optional)
+     * @param enumFormStringArray Form parameter enum test (string array) (optional, default to $)
+     * @param enumFormString Form parameter enum test (string) (optional, default to -efg)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void testEnumParameters(List<String> enumHeaderStringArray, String enumHeaderString, List<String> enumQueryStringArray, String enumQueryString, Integer enumQueryInteger, Double enumQueryDouble, List<String> enumFormStringArray, String enumFormString) throws RestClientException {
+        testEnumParametersWithHttpInfo(enumHeaderStringArray, enumHeaderString, enumQueryStringArray, enumQueryString, enumQueryInteger, enumQueryDouble, enumFormStringArray, enumFormString);
+    }
+
+    /**
+     * To test enum parameters
+     * To test enum parameters
+     * <p><b>400</b> - Invalid request
+     * <p><b>404</b> - Not found
+     * @param enumHeaderStringArray Header parameter enum test (string array) (optional, default to new ArrayList&lt;String&gt;())
+     * @param enumHeaderString Header parameter enum test (string) (optional, default to -efg)
+     * @param enumQueryStringArray Query parameter enum test (string array) (optional, default to new ArrayList&lt;String&gt;())
+     * @param enumQueryString Query parameter enum test (string) (optional, default to -efg)
+     * @param enumQueryInteger Query parameter enum test (double) (optional)
+     * @param enumQueryDouble Query parameter enum test (double) (optional)
+     * @param enumFormStringArray Form parameter enum test (string array) (optional, default to $)
+     * @param enumFormString Form parameter enum test (string) (optional, default to -efg)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> testEnumParametersWithHttpInfo(List<String> enumHeaderStringArray, String enumHeaderString, List<String> enumQueryStringArray, String enumQueryString, Integer enumQueryInteger, Double enumQueryDouble, List<String> enumFormStringArray, String enumFormString) throws RestClientException {
         Object postBody = null;
         
         String path = apiClient.expandPath("/fake", Collections.<String, Object>emptyMap());
@@ -454,21 +598,38 @@ public void testEnumParameters(List<String> enumHeaderStringArray, String enumHe
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.GET, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.GET, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * Fake endpoint to test group parameters (optional)
      * Fake endpoint to test group parameters (optional)
      * <p><b>400</b> - Someting wrong
-     * @param requiredStringGroup Required String in group parameters
-     * @param requiredBooleanGroup Required Boolean in group parameters
-     * @param requiredInt64Group Required Integer in group parameters
-     * @param stringGroup String in group parameters
-     * @param booleanGroup Boolean in group parameters
-     * @param int64Group Integer in group parameters
+     * @param requiredStringGroup Required String in group parameters (required)
+     * @param requiredBooleanGroup Required Boolean in group parameters (required)
+     * @param requiredInt64Group Required Integer in group parameters (required)
+     * @param stringGroup String in group parameters (optional)
+     * @param booleanGroup Boolean in group parameters (optional)
+     * @param int64Group Integer in group parameters (optional)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void testGroupParameters(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws RestClientException {
+        testGroupParametersWithHttpInfo(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
+    }
+
+    /**
+     * Fake endpoint to test group parameters (optional)
+     * Fake endpoint to test group parameters (optional)
+     * <p><b>400</b> - Someting wrong
+     * @param requiredStringGroup Required String in group parameters (required)
+     * @param requiredBooleanGroup Required Boolean in group parameters (required)
+     * @param requiredInt64Group Required Integer in group parameters (required)
+     * @param stringGroup String in group parameters (optional)
+     * @param booleanGroup Boolean in group parameters (optional)
+     * @param int64Group Integer in group parameters (optional)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> testGroupParametersWithHttpInfo(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'requiredStringGroup' is set
@@ -510,16 +671,28 @@ public void testGroupParameters(Integer requiredStringGroup, Boolean requiredBoo
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.DELETE, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.DELETE, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * test inline additionalProperties
      * 
      * <p><b>200</b> - successful operation
-     * @param param request body
+     * @param param request body (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void testInlineAdditionalProperties(Map<String, String> param) throws RestClientException {
+        testInlineAdditionalPropertiesWithHttpInfo(param);
+    }
+
+    /**
+     * test inline additionalProperties
+     * 
+     * <p><b>200</b> - successful operation
+     * @param param request body (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> testInlineAdditionalPropertiesWithHttpInfo(Map<String, String> param) throws RestClientException {
         Object postBody = param;
         
         // verify the required parameter 'param' is set
@@ -543,17 +716,30 @@ public void testInlineAdditionalProperties(Map<String, String> param) throws Res
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * test json serialization of form data
      * 
      * <p><b>200</b> - successful operation
-     * @param param field1
-     * @param param2 field2
+     * @param param field1 (required)
+     * @param param2 field2 (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void testJsonFormData(String param, String param2) throws RestClientException {
+        testJsonFormDataWithHttpInfo(param, param2);
+    }
+
+    /**
+     * test json serialization of form data
+     * 
+     * <p><b>200</b> - successful operation
+     * @param param field1 (required)
+     * @param param2 field2 (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> testJsonFormDataWithHttpInfo(String param, String param2) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'param' is set
@@ -587,20 +773,36 @@ public void testJsonFormData(String param, String param2) throws RestClientExcep
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.GET, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.GET, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * 
      * To test the collection format in query parameters
      * <p><b>200</b> - Success
-     * @param pipe The pipe parameter
-     * @param ioutil The ioutil parameter
-     * @param http The http parameter
-     * @param url The url parameter
-     * @param context The context parameter
+     * @param pipe  (required)
+     * @param ioutil  (required)
+     * @param http  (required)
+     * @param url  (required)
+     * @param context  (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void testQueryParameterCollectionFormat(List<String> pipe, List<String> ioutil, List<String> http, List<String> url, List<String> context) throws RestClientException {
+        testQueryParameterCollectionFormatWithHttpInfo(pipe, ioutil, http, url, context);
+    }
+
+    /**
+     * 
+     * To test the collection format in query parameters
+     * <p><b>200</b> - Success
+     * @param pipe  (required)
+     * @param ioutil  (required)
+     * @param http  (required)
+     * @param url  (required)
+     * @param context  (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> testQueryParameterCollectionFormatWithHttpInfo(List<String> pipe, List<String> ioutil, List<String> http, List<String> url, List<String> context) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'pipe' is set
@@ -648,6 +850,6 @@ public void testQueryParameterCollectionFormat(List<String> pipe, List<String> i
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.PUT, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.PUT, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
 }
diff --git a/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java b/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
index b619b51c261c..74d86633d8bb 100644
--- a/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
+++ b/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
@@ -24,6 +24,7 @@
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
 
 
 @Component("org.openapitools.client.api.FakeClassnameTags123Api")
@@ -51,11 +52,23 @@ public void setApiClient(ApiClient apiClient) {
      * To test class name in snake case
      * To test class name in snake case
      * <p><b>200</b> - successful operation
-     * @param body client model
+     * @param body client model (required)
      * @return Client
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public Client testClassname(Client body) throws RestClientException {
+        return testClassnameWithHttpInfo(body).getBody();
+    }
+
+    /**
+     * To test class name in snake case
+     * To test class name in snake case
+     * <p><b>200</b> - successful operation
+     * @param body client model (required)
+     * @return ResponseEntity&lt;Client&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Client> testClassnameWithHttpInfo(Client body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'body' is set
diff --git a/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/PetApi.java b/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/PetApi.java
index d012578f0fad..31c2f785a289 100644
--- a/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/PetApi.java
+++ b/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/PetApi.java
@@ -26,6 +26,7 @@
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
 
 
 @Component("org.openapitools.client.api.PetApi")
@@ -54,10 +55,23 @@ public void setApiClient(ApiClient apiClient) {
      * 
      * <p><b>200</b> - successful operation
      * <p><b>405</b> - Invalid input
-     * @param body Pet object that needs to be added to the store
+     * @param body Pet object that needs to be added to the store (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void addPet(Pet body) throws RestClientException {
+        addPetWithHttpInfo(body);
+    }
+
+    /**
+     * Add a new pet to the store
+     * 
+     * <p><b>200</b> - successful operation
+     * <p><b>405</b> - Invalid input
+     * @param body Pet object that needs to be added to the store (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> addPetWithHttpInfo(Pet body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'body' is set
@@ -81,18 +95,32 @@ public void addPet(Pet body) throws RestClientException {
         String[] authNames = new String[] { "petstore_auth" };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * Deletes a pet
      * 
      * <p><b>200</b> - successful operation
      * <p><b>400</b> - Invalid pet value
-     * @param petId Pet id to delete
-     * @param apiKey The apiKey parameter
+     * @param petId Pet id to delete (required)
+     * @param apiKey  (optional)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void deletePet(Long petId, String apiKey) throws RestClientException {
+        deletePetWithHttpInfo(petId, apiKey);
+    }
+
+    /**
+     * Deletes a pet
+     * 
+     * <p><b>200</b> - successful operation
+     * <p><b>400</b> - Invalid pet value
+     * @param petId Pet id to delete (required)
+     * @param apiKey  (optional)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> deletePetWithHttpInfo(Long petId, String apiKey) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'petId' is set
@@ -120,18 +148,31 @@ public void deletePet(Long petId, String apiKey) throws RestClientException {
         String[] authNames = new String[] { "petstore_auth" };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.DELETE, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.DELETE, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * Finds Pets by status
      * Multiple status values can be provided with comma separated strings
      * <p><b>200</b> - successful operation
      * <p><b>400</b> - Invalid status value
-     * @param status Status values that need to be considered for filter
+     * @param status Status values that need to be considered for filter (required)
      * @return List&lt;Pet&gt;
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public List<Pet> findPetsByStatus(List<String> status) throws RestClientException {
+        return findPetsByStatusWithHttpInfo(status).getBody();
+    }
+
+    /**
+     * Finds Pets by status
+     * Multiple status values can be provided with comma separated strings
+     * <p><b>200</b> - successful operation
+     * <p><b>400</b> - Invalid status value
+     * @param status Status values that need to be considered for filter (required)
+     * @return ResponseEntity&lt;List&lt;Pet&gt;&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<List<Pet>> findPetsByStatusWithHttpInfo(List<String> status) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'status' is set
@@ -164,11 +205,26 @@ public List<Pet> findPetsByStatus(List<String> status) throws RestClientExceptio
      * Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
      * <p><b>200</b> - successful operation
      * <p><b>400</b> - Invalid tag value
-     * @param tags Tags to filter by
+     * @param tags Tags to filter by (required)
      * @return List&lt;Pet&gt;
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
+    @Deprecated
     public List<Pet> findPetsByTags(List<String> tags) throws RestClientException {
+        return findPetsByTagsWithHttpInfo(tags).getBody();
+    }
+
+    /**
+     * Finds Pets by tags
+     * Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3 for testing.
+     * <p><b>200</b> - successful operation
+     * <p><b>400</b> - Invalid tag value
+     * @param tags Tags to filter by (required)
+     * @return ResponseEntity&lt;List&lt;Pet&gt;&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    @Deprecated
+    public ResponseEntity<List<Pet>> findPetsByTagsWithHttpInfo(List<String> tags) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'tags' is set
@@ -202,11 +258,25 @@ public List<Pet> findPetsByTags(List<String> tags) throws RestClientException {
      * <p><b>200</b> - successful operation
      * <p><b>400</b> - Invalid ID supplied
      * <p><b>404</b> - Pet not found
-     * @param petId ID of pet to return
+     * @param petId ID of pet to return (required)
      * @return Pet
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public Pet getPetById(Long petId) throws RestClientException {
+        return getPetByIdWithHttpInfo(petId).getBody();
+    }
+
+    /**
+     * Find pet by ID
+     * Returns a single pet
+     * <p><b>200</b> - successful operation
+     * <p><b>400</b> - Invalid ID supplied
+     * <p><b>404</b> - Pet not found
+     * @param petId ID of pet to return (required)
+     * @return ResponseEntity&lt;Pet&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Pet> getPetByIdWithHttpInfo(Long petId) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'petId' is set
@@ -242,10 +312,25 @@ public Pet getPetById(Long petId) throws RestClientException {
      * <p><b>400</b> - Invalid ID supplied
      * <p><b>404</b> - Pet not found
      * <p><b>405</b> - Validation exception
-     * @param body Pet object that needs to be added to the store
+     * @param body Pet object that needs to be added to the store (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void updatePet(Pet body) throws RestClientException {
+        updatePetWithHttpInfo(body);
+    }
+
+    /**
+     * Update an existing pet
+     * 
+     * <p><b>200</b> - successful operation
+     * <p><b>400</b> - Invalid ID supplied
+     * <p><b>404</b> - Pet not found
+     * <p><b>405</b> - Validation exception
+     * @param body Pet object that needs to be added to the store (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> updatePetWithHttpInfo(Pet body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'body' is set
@@ -269,18 +354,32 @@ public void updatePet(Pet body) throws RestClientException {
         String[] authNames = new String[] { "petstore_auth" };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.PUT, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.PUT, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * Updates a pet in the store with form data
      * 
      * <p><b>405</b> - Invalid input
-     * @param petId ID of pet that needs to be updated
-     * @param name Updated name of the pet
-     * @param status Updated status of the pet
+     * @param petId ID of pet that needs to be updated (required)
+     * @param name Updated name of the pet (optional)
+     * @param status Updated status of the pet (optional)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void updatePetWithForm(Long petId, String name, String status) throws RestClientException {
+        updatePetWithFormWithHttpInfo(petId, name, status);
+    }
+
+    /**
+     * Updates a pet in the store with form data
+     * 
+     * <p><b>405</b> - Invalid input
+     * @param petId ID of pet that needs to be updated (required)
+     * @param name Updated name of the pet (optional)
+     * @param status Updated status of the pet (optional)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> updatePetWithFormWithHttpInfo(Long petId, String name, String status) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'petId' is set
@@ -312,19 +411,33 @@ public void updatePetWithForm(Long petId, String name, String status) throws Res
         String[] authNames = new String[] { "petstore_auth" };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * uploads an image
      * 
      * <p><b>200</b> - successful operation
-     * @param petId ID of pet to update
-     * @param additionalMetadata Additional data to pass to server
-     * @param file file to upload
+     * @param petId ID of pet to update (required)
+     * @param additionalMetadata Additional data to pass to server (optional)
+     * @param file file to upload (optional)
      * @return ModelApiResponse
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public ModelApiResponse uploadFile(Long petId, String additionalMetadata, File file) throws RestClientException {
+        return uploadFileWithHttpInfo(petId, additionalMetadata, file).getBody();
+    }
+
+    /**
+     * uploads an image
+     * 
+     * <p><b>200</b> - successful operation
+     * @param petId ID of pet to update (required)
+     * @param additionalMetadata Additional data to pass to server (optional)
+     * @param file file to upload (optional)
+     * @return ResponseEntity&lt;ModelApiResponse&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<ModelApiResponse> uploadFileWithHttpInfo(Long petId, String additionalMetadata, File file) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'petId' is set
@@ -364,13 +477,27 @@ public ModelApiResponse uploadFile(Long petId, String additionalMetadata, File f
      * uploads an image (required)
      * 
      * <p><b>200</b> - successful operation
-     * @param petId ID of pet to update
-     * @param requiredFile file to upload
-     * @param additionalMetadata Additional data to pass to server
+     * @param petId ID of pet to update (required)
+     * @param requiredFile file to upload (required)
+     * @param additionalMetadata Additional data to pass to server (optional)
      * @return ModelApiResponse
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public ModelApiResponse uploadFileWithRequiredFile(Long petId, File requiredFile, String additionalMetadata) throws RestClientException {
+        return uploadFileWithRequiredFileWithHttpInfo(petId, requiredFile, additionalMetadata).getBody();
+    }
+
+    /**
+     * uploads an image (required)
+     * 
+     * <p><b>200</b> - successful operation
+     * @param petId ID of pet to update (required)
+     * @param requiredFile file to upload (required)
+     * @param additionalMetadata Additional data to pass to server (optional)
+     * @return ResponseEntity&lt;ModelApiResponse&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<ModelApiResponse> uploadFileWithRequiredFileWithHttpInfo(Long petId, File requiredFile, String additionalMetadata) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'petId' is set
diff --git a/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/StoreApi.java b/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/StoreApi.java
index 4488bd0ae0a4..29b990a85d1d 100644
--- a/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/StoreApi.java
+++ b/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/StoreApi.java
@@ -24,6 +24,7 @@
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
 
 
 @Component("org.openapitools.client.api.StoreApi")
@@ -52,10 +53,23 @@ public void setApiClient(ApiClient apiClient) {
      * For valid response try integer IDs with value &lt; 1000. Anything above 1000 or nonintegers will generate API errors
      * <p><b>400</b> - Invalid ID supplied
      * <p><b>404</b> - Order not found
-     * @param orderId ID of the order that needs to be deleted
+     * @param orderId ID of the order that needs to be deleted (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void deleteOrder(String orderId) throws RestClientException {
+        deleteOrderWithHttpInfo(orderId);
+    }
+
+    /**
+     * Delete purchase order by ID
+     * For valid response try integer IDs with value &lt; 1000. Anything above 1000 or nonintegers will generate API errors
+     * <p><b>400</b> - Invalid ID supplied
+     * <p><b>404</b> - Order not found
+     * @param orderId ID of the order that needs to be deleted (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> deleteOrderWithHttpInfo(String orderId) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'orderId' is set
@@ -80,7 +94,7 @@ public void deleteOrder(String orderId) throws RestClientException {
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.DELETE, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.DELETE, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * Returns pet inventories by status
@@ -90,6 +104,17 @@ public void deleteOrder(String orderId) throws RestClientException {
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public Map<String, Integer> getInventory() throws RestClientException {
+        return getInventoryWithHttpInfo().getBody();
+    }
+
+    /**
+     * Returns pet inventories by status
+     * Returns a map of status codes to quantities
+     * <p><b>200</b> - successful operation
+     * @return ResponseEntity&lt;Map&lt;String, Integer&gt;&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Map<String, Integer>> getInventoryWithHttpInfo() throws RestClientException {
         Object postBody = null;
         
         String path = apiClient.expandPath("/store/inventory", Collections.<String, Object>emptyMap());
@@ -116,11 +141,25 @@ public Map<String, Integer> getInventory() throws RestClientException {
      * <p><b>200</b> - successful operation
      * <p><b>400</b> - Invalid ID supplied
      * <p><b>404</b> - Order not found
-     * @param orderId ID of pet that needs to be fetched
+     * @param orderId ID of pet that needs to be fetched (required)
      * @return Order
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public Order getOrderById(Long orderId) throws RestClientException {
+        return getOrderByIdWithHttpInfo(orderId).getBody();
+    }
+
+    /**
+     * Find purchase order by ID
+     * For valid response try integer IDs with value &lt;&#x3D; 5 or &gt; 10. Other values will generated exceptions
+     * <p><b>200</b> - successful operation
+     * <p><b>400</b> - Invalid ID supplied
+     * <p><b>404</b> - Order not found
+     * @param orderId ID of pet that needs to be fetched (required)
+     * @return ResponseEntity&lt;Order&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Order> getOrderByIdWithHttpInfo(Long orderId) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'orderId' is set
@@ -154,11 +193,24 @@ public Order getOrderById(Long orderId) throws RestClientException {
      * 
      * <p><b>200</b> - successful operation
      * <p><b>400</b> - Invalid Order
-     * @param body order placed for purchasing the pet
+     * @param body order placed for purchasing the pet (required)
      * @return Order
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public Order placeOrder(Order body) throws RestClientException {
+        return placeOrderWithHttpInfo(body).getBody();
+    }
+
+    /**
+     * Place an order for a pet
+     * 
+     * <p><b>200</b> - successful operation
+     * <p><b>400</b> - Invalid Order
+     * @param body order placed for purchasing the pet (required)
+     * @return ResponseEntity&lt;Order&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Order> placeOrderWithHttpInfo(Order body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'body' is set
diff --git a/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/UserApi.java b/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/UserApi.java
index 1d2d59616b6d..66db8e8cd145 100644
--- a/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/UserApi.java
+++ b/samples/client/petstore/java/resttemplate/src/main/java/org/openapitools/client/api/UserApi.java
@@ -24,6 +24,7 @@
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
 
 
 @Component("org.openapitools.client.api.UserApi")
@@ -51,10 +52,22 @@ public void setApiClient(ApiClient apiClient) {
      * Create user
      * This can only be done by the logged in user.
      * <p><b>0</b> - successful operation
-     * @param body Created user object
+     * @param body Created user object (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void createUser(User body) throws RestClientException {
+        createUserWithHttpInfo(body);
+    }
+
+    /**
+     * Create user
+     * This can only be done by the logged in user.
+     * <p><b>0</b> - successful operation
+     * @param body Created user object (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> createUserWithHttpInfo(User body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'body' is set
@@ -76,16 +89,28 @@ public void createUser(User body) throws RestClientException {
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * Creates list of users with given input array
      * 
      * <p><b>0</b> - successful operation
-     * @param body List of user object
+     * @param body List of user object (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void createUsersWithArrayInput(List<User> body) throws RestClientException {
+        createUsersWithArrayInputWithHttpInfo(body);
+    }
+
+    /**
+     * Creates list of users with given input array
+     * 
+     * <p><b>0</b> - successful operation
+     * @param body List of user object (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> createUsersWithArrayInputWithHttpInfo(List<User> body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'body' is set
@@ -107,16 +132,28 @@ public void createUsersWithArrayInput(List<User> body) throws RestClientExceptio
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * Creates list of users with given input array
      * 
      * <p><b>0</b> - successful operation
-     * @param body List of user object
+     * @param body List of user object (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void createUsersWithListInput(List<User> body) throws RestClientException {
+        createUsersWithListInputWithHttpInfo(body);
+    }
+
+    /**
+     * Creates list of users with given input array
+     * 
+     * <p><b>0</b> - successful operation
+     * @param body List of user object (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> createUsersWithListInputWithHttpInfo(List<User> body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'body' is set
@@ -138,17 +175,30 @@ public void createUsersWithListInput(List<User> body) throws RestClientException
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.POST, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * Delete user
      * This can only be done by the logged in user.
      * <p><b>400</b> - Invalid username supplied
      * <p><b>404</b> - User not found
-     * @param username The name that needs to be deleted
+     * @param username The name that needs to be deleted (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void deleteUser(String username) throws RestClientException {
+        deleteUserWithHttpInfo(username);
+    }
+
+    /**
+     * Delete user
+     * This can only be done by the logged in user.
+     * <p><b>400</b> - Invalid username supplied
+     * <p><b>404</b> - User not found
+     * @param username The name that needs to be deleted (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> deleteUserWithHttpInfo(String username) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'username' is set
@@ -173,7 +223,7 @@ public void deleteUser(String username) throws RestClientException {
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.DELETE, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.DELETE, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * Get user by user name
@@ -181,11 +231,25 @@ public void deleteUser(String username) throws RestClientException {
      * <p><b>200</b> - successful operation
      * <p><b>400</b> - Invalid username supplied
      * <p><b>404</b> - User not found
-     * @param username The name that needs to be fetched. Use user1 for testing.
+     * @param username The name that needs to be fetched. Use user1 for testing. (required)
      * @return User
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public User getUserByName(String username) throws RestClientException {
+        return getUserByNameWithHttpInfo(username).getBody();
+    }
+
+    /**
+     * Get user by user name
+     * 
+     * <p><b>200</b> - successful operation
+     * <p><b>400</b> - Invalid username supplied
+     * <p><b>404</b> - User not found
+     * @param username The name that needs to be fetched. Use user1 for testing. (required)
+     * @return ResponseEntity&lt;User&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<User> getUserByNameWithHttpInfo(String username) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'username' is set
@@ -219,12 +283,26 @@ public User getUserByName(String username) throws RestClientException {
      * 
      * <p><b>200</b> - successful operation
      * <p><b>400</b> - Invalid username/password supplied
-     * @param username The user name for login
-     * @param password The password for login in clear text
+     * @param username The user name for login (required)
+     * @param password The password for login in clear text (required)
      * @return String
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public String loginUser(String username, String password) throws RestClientException {
+        return loginUserWithHttpInfo(username, password).getBody();
+    }
+
+    /**
+     * Logs user into the system
+     * 
+     * <p><b>200</b> - successful operation
+     * <p><b>400</b> - Invalid username/password supplied
+     * @param username The user name for login (required)
+     * @param password The password for login in clear text (required)
+     * @return ResponseEntity&lt;String&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<String> loginUserWithHttpInfo(String username, String password) throws RestClientException {
         Object postBody = null;
         
         // verify the required parameter 'username' is set
@@ -265,6 +343,17 @@ public String loginUser(String username, String password) throws RestClientExcep
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void logoutUser() throws RestClientException {
+        logoutUserWithHttpInfo();
+    }
+
+    /**
+     * Logs out current logged in user session
+     * 
+     * <p><b>0</b> - successful operation
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> logoutUserWithHttpInfo() throws RestClientException {
         Object postBody = null;
         
         String path = apiClient.expandPath("/user/logout", Collections.<String, Object>emptyMap());
@@ -281,18 +370,32 @@ public void logoutUser() throws RestClientException {
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.GET, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.GET, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
     /**
      * Updated user
      * This can only be done by the logged in user.
      * <p><b>400</b> - Invalid user supplied
      * <p><b>404</b> - User not found
-     * @param username name that need to be deleted
-     * @param body Updated user object
+     * @param username name that need to be deleted (required)
+     * @param body Updated user object (required)
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
     public void updateUser(String username, User body) throws RestClientException {
+        updateUserWithHttpInfo(username, body);
+    }
+
+    /**
+     * Updated user
+     * This can only be done by the logged in user.
+     * <p><b>400</b> - Invalid user supplied
+     * <p><b>404</b> - User not found
+     * @param username name that need to be deleted (required)
+     * @param body Updated user object (required)
+     * @return ResponseEntity&lt;Void&gt;
+     * @throws RestClientException if an error occurs while attempting to invoke the API
+     */
+    public ResponseEntity<Void> updateUserWithHttpInfo(String username, User body) throws RestClientException {
         Object postBody = body;
         
         // verify the required parameter 'username' is set
@@ -322,6 +425,6 @@ public void updateUser(String username, User body) throws RestClientException {
         String[] authNames = new String[] {  };
 
         ParameterizedTypeReference<Void> returnType = new ParameterizedTypeReference<Void>() {};
-        apiClient.invokeAPI(path, HttpMethod.PUT, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
+        return apiClient.invokeAPI(path, HttpMethod.PUT, queryParams, postBody, headerParams, formParams, accept, contentType, authNames, returnType);
     }
 }