diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultGenerator.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultGenerator.java
index e21b7cf3bab..4128fb71b3d 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultGenerator.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultGenerator.java
@@ -170,7 +170,6 @@ public class DefaultGenerator extends AbstractGenerator implements Generator {
             config.additionalProperties().put(CodegenConstants.EXCLUDE_TESTS, true);
         }
 
-
         if (System.getProperty("debugOpenAPI") != null) {
             Json.prettyPrint(openAPI);
         } else if (System.getProperty("debugSwagger") != null) {
@@ -528,6 +527,21 @@ public class DefaultGenerator extends AbstractGenerator implements Generator {
                     operation.put("vendorExtensions", config.vendorExtensions());
                 }
 
+                // process top-level x-group-parameters
+                if (config.vendorExtensions().containsKey("x-group-parameters")) {
+                    Boolean isGroupParameters = Boolean.valueOf(config.vendorExtensions().get("x-group-parameters").toString());
+
+                    Map<String, Object> objectMap = (Map<String, Object>) operation.get("operations");
+                    @SuppressWarnings("unchecked")
+                    List<CodegenOperation> operations = (List<CodegenOperation>) objectMap.get("operation");
+                    for (CodegenOperation op : operations) {
+                        op.httpMethod = op.httpMethod.toLowerCase(Locale.ROOT);
+                        if (!op.vendorExtensions.containsKey("x-group-parameters")) {
+                            op.vendorExtensions.put("x-group-parameters", Boolean.TRUE);
+                        }
+                    }
+                }
+
                 // Pass sortParamsByRequiredFlag through to the Mustache template...
                 boolean sortParamsByRequiredFlag = true;
                 if (this.config.additionalProperties().containsKey(CodegenConstants.SORT_PARAMS_BY_REQUIRED_FLAG)) {
@@ -1056,6 +1070,7 @@ public class DefaultGenerator extends AbstractGenerator implements Generator {
         if (imports.size() > 0) {
             operations.put("hasImport", true);
         }
+
         config.postProcessOperations(operations);
         config.postProcessOperationsWithModels(operations, allModels);
         if (objs.size() > 0) {
diff --git a/modules/openapi-generator/src/test/resources/2_0/petstore-with-fake-endpoints-models-for-testing.yaml b/modules/openapi-generator/src/test/resources/2_0/petstore-with-fake-endpoints-models-for-testing.yaml
index 4307bdc0eb5..2a57404e601 100644
--- a/modules/openapi-generator/src/test/resources/2_0/petstore-with-fake-endpoints-models-for-testing.yaml
+++ b/modules/openapi-generator/src/test/resources/2_0/petstore-with-fake-endpoints-models-for-testing.yaml
@@ -800,6 +800,22 @@ paths:
       operationId: testGroupParameters
       x-group-parameters: true
       parameters:
+        - name: required_string_group
+          type: integer
+          in: query
+          description: Required String in group parameters
+          required: true
+        - name: required_boolean_group
+          type: boolean
+          in: header
+          description: Required Boolean in group parameters
+          required: true
+        - name: required_int64_group
+          type: integer
+          format: int64
+          in: query
+          description: Required Integer in group parameters
+          required: true
         - name: string_group
           type: integer
           in: query
diff --git a/modules/openapi-generator/src/test/resources/3_0/petstore-with-fake-endpoints-models-for-testing.yaml b/modules/openapi-generator/src/test/resources/3_0/petstore-with-fake-endpoints-models-for-testing.yaml
index d60c17ddc3a..563ca99bc94 100644
--- a/modules/openapi-generator/src/test/resources/3_0/petstore-with-fake-endpoints-models-for-testing.yaml
+++ b/modules/openapi-generator/src/test/resources/3_0/petstore-with-fake-endpoints-models-for-testing.yaml
@@ -773,6 +773,25 @@ paths:
       operationId: testGroupParameters
       x-group-parameters: true
       parameters:
+        - name: required_string_group
+          in: query
+          description: Required String in group parameters
+          required: true
+          schema:
+            type: integer
+        - name: required_boolean_group
+          in: header
+          description: Required Boolean in group parameters
+          required: true
+          schema:
+            type: boolean
+        - name: required_int64_group
+          in: query
+          description: Required Integer in group parameters
+          required: true
+          schema:
+            type: integer
+            format: int64
         - name: string_group
           in: query
           description: String in group parameters
diff --git a/samples/client/petstore/csharp/OpenAPIClient/docs/FakeApi.md b/samples/client/petstore/csharp/OpenAPIClient/docs/FakeApi.md
index d9f2c5dc7f3..5be422501cd 100644
--- a/samples/client/petstore/csharp/OpenAPIClient/docs/FakeApi.md
+++ b/samples/client/petstore/csharp/OpenAPIClient/docs/FakeApi.md
@@ -603,7 +603,7 @@ No authorization required
 
 <a name="testgroupparameters"></a>
 # **TestGroupParameters**
-> void TestGroupParameters (int? stringGroup = null, bool? booleanGroup = null, long? int64Group = null)
+> void TestGroupParameters (int? requiredStringGroup, bool? requiredBooleanGroup, long? requiredInt64Group, int? stringGroup = null, bool? booleanGroup = null, long? int64Group = null)
 
 Fake endpoint to test group parameters (optional)
 
@@ -624,6 +624,9 @@ namespace Example
         public void main()
         {
             var apiInstance = new FakeApi();
+            var requiredStringGroup = 56;  // int? | Required String in group parameters
+            var requiredBooleanGroup = true;  // bool? | Required Boolean in group parameters
+            var requiredInt64Group = 789;  // long? | Required Integer in group parameters
             var stringGroup = 56;  // int? | String in group parameters (optional) 
             var booleanGroup = true;  // bool? | Boolean in group parameters (optional) 
             var int64Group = 789;  // long? | Integer in group parameters (optional) 
@@ -631,7 +634,7 @@ namespace Example
             try
             {
                 // Fake endpoint to test group parameters (optional)
-                apiInstance.TestGroupParameters(stringGroup, booleanGroup, int64Group);
+                apiInstance.TestGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
             }
             catch (Exception e)
             {
@@ -646,6 +649,9 @@ namespace Example
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **requiredStringGroup** | **int?**| Required String in group parameters | 
+ **requiredBooleanGroup** | **bool?**| Required Boolean in group parameters | 
+ **requiredInt64Group** | **long?**| Required Integer in group parameters | 
  **stringGroup** | **int?**| String in group parameters | [optional] 
  **booleanGroup** | **bool?**| Boolean in group parameters | [optional] 
  **int64Group** | **long?**| Integer in group parameters | [optional] 
diff --git a/samples/client/petstore/csharp/OpenAPIClient/src/Org.OpenAPITools/Api/FakeApi.cs b/samples/client/petstore/csharp/OpenAPIClient/src/Org.OpenAPITools/Api/FakeApi.cs
index 283b7db9dc2..5de355ea7db 100644
--- a/samples/client/petstore/csharp/OpenAPIClient/src/Org.OpenAPITools/Api/FakeApi.cs
+++ b/samples/client/petstore/csharp/OpenAPIClient/src/Org.OpenAPITools/Api/FakeApi.cs
@@ -262,11 +262,14 @@ namespace Org.OpenAPITools.Api
         /// Fake endpoint to test group parameters (optional)
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringGroup">Required String in group parameters</param>
+        /// <param name="requiredBooleanGroup">Required Boolean in group parameters</param>
+        /// <param name="requiredInt64Group">Required Integer in group parameters</param>
         /// <param name="stringGroup">String in group parameters (optional)</param>
         /// <param name="booleanGroup">Boolean in group parameters (optional)</param>
         /// <param name="int64Group">Integer in group parameters (optional)</param>
         /// <returns></returns>
-        void TestGroupParameters (int? stringGroup = null, bool? booleanGroup = null, long? int64Group = null);
+        void TestGroupParameters (int? requiredStringGroup, bool? requiredBooleanGroup, long? requiredInt64Group, int? stringGroup = null, bool? booleanGroup = null, long? int64Group = null);
 
         /// <summary>
         /// Fake endpoint to test group parameters (optional)
@@ -275,11 +278,14 @@ namespace Org.OpenAPITools.Api
         /// Fake endpoint to test group parameters (optional)
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringGroup">Required String in group parameters</param>
+        /// <param name="requiredBooleanGroup">Required Boolean in group parameters</param>
+        /// <param name="requiredInt64Group">Required Integer in group parameters</param>
         /// <param name="stringGroup">String in group parameters (optional)</param>
         /// <param name="booleanGroup">Boolean in group parameters (optional)</param>
         /// <param name="int64Group">Integer in group parameters (optional)</param>
         /// <returns>ApiResponse of Object(void)</returns>
-        ApiResponse<Object> TestGroupParametersWithHttpInfo (int? stringGroup = null, bool? booleanGroup = null, long? int64Group = null);
+        ApiResponse<Object> TestGroupParametersWithHttpInfo (int? requiredStringGroup, bool? requiredBooleanGroup, long? requiredInt64Group, int? stringGroup = null, bool? booleanGroup = null, long? int64Group = null);
         /// <summary>
         /// test inline additionalProperties
         /// </summary>
@@ -564,11 +570,14 @@ namespace Org.OpenAPITools.Api
         /// Fake endpoint to test group parameters (optional)
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringGroup">Required String in group parameters</param>
+        /// <param name="requiredBooleanGroup">Required Boolean in group parameters</param>
+        /// <param name="requiredInt64Group">Required Integer in group parameters</param>
         /// <param name="stringGroup">String in group parameters (optional)</param>
         /// <param name="booleanGroup">Boolean in group parameters (optional)</param>
         /// <param name="int64Group">Integer in group parameters (optional)</param>
         /// <returns>Task of void</returns>
-        System.Threading.Tasks.Task TestGroupParametersAsync (int? stringGroup = null, bool? booleanGroup = null, long? int64Group = null);
+        System.Threading.Tasks.Task TestGroupParametersAsync (int? requiredStringGroup, bool? requiredBooleanGroup, long? requiredInt64Group, int? stringGroup = null, bool? booleanGroup = null, long? int64Group = null);
 
         /// <summary>
         /// Fake endpoint to test group parameters (optional)
@@ -577,11 +586,14 @@ namespace Org.OpenAPITools.Api
         /// Fake endpoint to test group parameters (optional)
         /// </remarks>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringGroup">Required String in group parameters</param>
+        /// <param name="requiredBooleanGroup">Required Boolean in group parameters</param>
+        /// <param name="requiredInt64Group">Required Integer in group parameters</param>
         /// <param name="stringGroup">String in group parameters (optional)</param>
         /// <param name="booleanGroup">Boolean in group parameters (optional)</param>
         /// <param name="int64Group">Integer in group parameters (optional)</param>
         /// <returns>Task of ApiResponse</returns>
-        System.Threading.Tasks.Task<ApiResponse<Object>> TestGroupParametersAsyncWithHttpInfo (int? stringGroup = null, bool? booleanGroup = null, long? int64Group = null);
+        System.Threading.Tasks.Task<ApiResponse<Object>> TestGroupParametersAsyncWithHttpInfo (int? requiredStringGroup, bool? requiredBooleanGroup, long? requiredInt64Group, int? stringGroup = null, bool? booleanGroup = null, long? int64Group = null);
         /// <summary>
         /// test inline additionalProperties
         /// </summary>
@@ -2162,25 +2174,40 @@ namespace Org.OpenAPITools.Api
         /// Fake endpoint to test group parameters (optional) Fake endpoint to test group parameters (optional)
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringGroup">Required String in group parameters</param>
+        /// <param name="requiredBooleanGroup">Required Boolean in group parameters</param>
+        /// <param name="requiredInt64Group">Required Integer in group parameters</param>
         /// <param name="stringGroup">String in group parameters (optional)</param>
         /// <param name="booleanGroup">Boolean in group parameters (optional)</param>
         /// <param name="int64Group">Integer in group parameters (optional)</param>
         /// <returns></returns>
-        public void TestGroupParameters (int? stringGroup = null, bool? booleanGroup = null, long? int64Group = null)
+        public void TestGroupParameters (int? requiredStringGroup, bool? requiredBooleanGroup, long? requiredInt64Group, int? stringGroup = null, bool? booleanGroup = null, long? int64Group = null)
         {
-             TestGroupParametersWithHttpInfo(stringGroup, booleanGroup, int64Group);
+             TestGroupParametersWithHttpInfo(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
         }
 
         /// <summary>
         /// Fake endpoint to test group parameters (optional) Fake endpoint to test group parameters (optional)
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringGroup">Required String in group parameters</param>
+        /// <param name="requiredBooleanGroup">Required Boolean in group parameters</param>
+        /// <param name="requiredInt64Group">Required Integer in group parameters</param>
         /// <param name="stringGroup">String in group parameters (optional)</param>
         /// <param name="booleanGroup">Boolean in group parameters (optional)</param>
         /// <param name="int64Group">Integer in group parameters (optional)</param>
         /// <returns>ApiResponse of Object(void)</returns>
-        public ApiResponse<Object> TestGroupParametersWithHttpInfo (int? stringGroup = null, bool? booleanGroup = null, long? int64Group = null)
+        public ApiResponse<Object> TestGroupParametersWithHttpInfo (int? requiredStringGroup, bool? requiredBooleanGroup, long? requiredInt64Group, int? stringGroup = null, bool? booleanGroup = null, long? int64Group = null)
         {
+            // verify the required parameter 'requiredStringGroup' is set
+            if (requiredStringGroup == null)
+                throw new ApiException(400, "Missing required parameter 'requiredStringGroup' when calling FakeApi->TestGroupParameters");
+            // verify the required parameter 'requiredBooleanGroup' is set
+            if (requiredBooleanGroup == null)
+                throw new ApiException(400, "Missing required parameter 'requiredBooleanGroup' when calling FakeApi->TestGroupParameters");
+            // verify the required parameter 'requiredInt64Group' is set
+            if (requiredInt64Group == null)
+                throw new ApiException(400, "Missing required parameter 'requiredInt64Group' when calling FakeApi->TestGroupParameters");
 
             var localVarPath = "/fake";
             var localVarPathParams = new Dictionary<String, String>();
@@ -2202,8 +2229,11 @@ namespace Org.OpenAPITools.Api
             if (localVarHttpHeaderAccept != null)
                 localVarHeaderParams.Add("Accept", localVarHttpHeaderAccept);
 
+            if (requiredStringGroup != null) localVarQueryParams.AddRange(this.Configuration.ApiClient.ParameterToKeyValuePairs("", "required_string_group", requiredStringGroup)); // query parameter
+            if (requiredInt64Group != null) localVarQueryParams.AddRange(this.Configuration.ApiClient.ParameterToKeyValuePairs("", "required_int64_group", requiredInt64Group)); // query parameter
             if (stringGroup != null) localVarQueryParams.AddRange(this.Configuration.ApiClient.ParameterToKeyValuePairs("", "string_group", stringGroup)); // query parameter
             if (int64Group != null) localVarQueryParams.AddRange(this.Configuration.ApiClient.ParameterToKeyValuePairs("", "int64_group", int64Group)); // query parameter
+            if (requiredBooleanGroup != null) localVarHeaderParams.Add("required_boolean_group", this.Configuration.ApiClient.ParameterToString(requiredBooleanGroup)); // header parameter
             if (booleanGroup != null) localVarHeaderParams.Add("boolean_group", this.Configuration.ApiClient.ParameterToString(booleanGroup)); // header parameter
 
 
@@ -2229,13 +2259,16 @@ namespace Org.OpenAPITools.Api
         /// Fake endpoint to test group parameters (optional) Fake endpoint to test group parameters (optional)
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringGroup">Required String in group parameters</param>
+        /// <param name="requiredBooleanGroup">Required Boolean in group parameters</param>
+        /// <param name="requiredInt64Group">Required Integer in group parameters</param>
         /// <param name="stringGroup">String in group parameters (optional)</param>
         /// <param name="booleanGroup">Boolean in group parameters (optional)</param>
         /// <param name="int64Group">Integer in group parameters (optional)</param>
         /// <returns>Task of void</returns>
-        public async System.Threading.Tasks.Task TestGroupParametersAsync (int? stringGroup = null, bool? booleanGroup = null, long? int64Group = null)
+        public async System.Threading.Tasks.Task TestGroupParametersAsync (int? requiredStringGroup, bool? requiredBooleanGroup, long? requiredInt64Group, int? stringGroup = null, bool? booleanGroup = null, long? int64Group = null)
         {
-             await TestGroupParametersAsyncWithHttpInfo(stringGroup, booleanGroup, int64Group);
+             await TestGroupParametersAsyncWithHttpInfo(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 
         }
 
@@ -2243,12 +2276,24 @@ namespace Org.OpenAPITools.Api
         /// Fake endpoint to test group parameters (optional) Fake endpoint to test group parameters (optional)
         /// </summary>
         /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
+        /// <param name="requiredStringGroup">Required String in group parameters</param>
+        /// <param name="requiredBooleanGroup">Required Boolean in group parameters</param>
+        /// <param name="requiredInt64Group">Required Integer in group parameters</param>
         /// <param name="stringGroup">String in group parameters (optional)</param>
         /// <param name="booleanGroup">Boolean in group parameters (optional)</param>
         /// <param name="int64Group">Integer in group parameters (optional)</param>
         /// <returns>Task of ApiResponse</returns>
-        public async System.Threading.Tasks.Task<ApiResponse<Object>> TestGroupParametersAsyncWithHttpInfo (int? stringGroup = null, bool? booleanGroup = null, long? int64Group = null)
+        public async System.Threading.Tasks.Task<ApiResponse<Object>> TestGroupParametersAsyncWithHttpInfo (int? requiredStringGroup, bool? requiredBooleanGroup, long? requiredInt64Group, int? stringGroup = null, bool? booleanGroup = null, long? int64Group = null)
         {
+            // verify the required parameter 'requiredStringGroup' is set
+            if (requiredStringGroup == null)
+                throw new ApiException(400, "Missing required parameter 'requiredStringGroup' when calling FakeApi->TestGroupParameters");
+            // verify the required parameter 'requiredBooleanGroup' is set
+            if (requiredBooleanGroup == null)
+                throw new ApiException(400, "Missing required parameter 'requiredBooleanGroup' when calling FakeApi->TestGroupParameters");
+            // verify the required parameter 'requiredInt64Group' is set
+            if (requiredInt64Group == null)
+                throw new ApiException(400, "Missing required parameter 'requiredInt64Group' when calling FakeApi->TestGroupParameters");
 
             var localVarPath = "/fake";
             var localVarPathParams = new Dictionary<String, String>();
@@ -2270,8 +2315,11 @@ namespace Org.OpenAPITools.Api
             if (localVarHttpHeaderAccept != null)
                 localVarHeaderParams.Add("Accept", localVarHttpHeaderAccept);
 
+            if (requiredStringGroup != null) localVarQueryParams.AddRange(this.Configuration.ApiClient.ParameterToKeyValuePairs("", "required_string_group", requiredStringGroup)); // query parameter
+            if (requiredInt64Group != null) localVarQueryParams.AddRange(this.Configuration.ApiClient.ParameterToKeyValuePairs("", "required_int64_group", requiredInt64Group)); // query parameter
             if (stringGroup != null) localVarQueryParams.AddRange(this.Configuration.ApiClient.ParameterToKeyValuePairs("", "string_group", stringGroup)); // query parameter
             if (int64Group != null) localVarQueryParams.AddRange(this.Configuration.ApiClient.ParameterToKeyValuePairs("", "int64_group", int64Group)); // query parameter
+            if (requiredBooleanGroup != null) localVarHeaderParams.Add("required_boolean_group", this.Configuration.ApiClient.ParameterToString(requiredBooleanGroup)); // header parameter
             if (booleanGroup != null) localVarHeaderParams.Add("boolean_group", this.Configuration.ApiClient.ParameterToString(booleanGroup)); // header parameter
 
 
diff --git a/samples/client/petstore/go/go-petstore/api/openapi.yaml b/samples/client/petstore/go/go-petstore/api/openapi.yaml
index 95a925396fa..40878d2c58d 100644
--- a/samples/client/petstore/go/go-petstore/api/openapi.yaml
+++ b/samples/client/petstore/go/go-petstore/api/openapi.yaml
@@ -593,6 +593,25 @@ paths:
       description: Fake endpoint to test group parameters (optional)
       operationId: testGroupParameters
       parameters:
+      - description: Required String in group parameters
+        in: query
+        name: required_string_group
+        required: true
+        schema:
+          type: integer
+      - description: Required Boolean in group parameters
+        in: header
+        name: required_boolean_group
+        required: true
+        schema:
+          type: boolean
+      - description: Required Integer in group parameters
+        in: query
+        name: required_int64_group
+        required: true
+        schema:
+          format: int64
+          type: integer
       - description: String in group parameters
         in: query
         name: string_group
diff --git a/samples/client/petstore/go/go-petstore/api_fake.go b/samples/client/petstore/go/go-petstore/api_fake.go
index f3792213114..4b6efb216fc 100644
--- a/samples/client/petstore/go/go-petstore/api_fake.go
+++ b/samples/client/petstore/go/go-petstore/api_fake.go
@@ -914,6 +914,9 @@ func (a *FakeApiService) TestEnumParameters(ctx context.Context, localVarOptiona
 FakeApiService Fake endpoint to test group parameters (optional)
 Fake endpoint to test group parameters (optional)
  * @param ctx context.Context - for authentication, logging, cancellation, deadlines, tracing, etc. Passed from http.Request or context.Background().
+ * @param requiredStringGroup Required String in group parameters
+ * @param requiredBooleanGroup Required Boolean in group parameters
+ * @param requiredInt64Group Required Integer in group parameters
  * @param optional nil or *TestGroupParametersOpts - Optional Parameters:
  * @param "StringGroup" (optional.Int32) -  String in group parameters
  * @param "BooleanGroup" (optional.Bool) -  Boolean in group parameters
@@ -926,7 +929,7 @@ type TestGroupParametersOpts struct {
 	Int64Group optional.Int64
 }
 
-func (a *FakeApiService) TestGroupParameters(ctx context.Context, localVarOptionals *TestGroupParametersOpts) (*http.Response, error) {
+func (a *FakeApiService) TestGroupParameters(ctx context.Context, requiredStringGroup int32, requiredBooleanGroup bool, requiredInt64Group int64, localVarOptionals *TestGroupParametersOpts) (*http.Response, error) {
 	var (
 		localVarHttpMethod   = strings.ToUpper("Delete")
 		localVarPostBody     interface{}
@@ -942,6 +945,8 @@ func (a *FakeApiService) TestGroupParameters(ctx context.Context, localVarOption
 	localVarQueryParams := url.Values{}
 	localVarFormParams := url.Values{}
 
+	localVarQueryParams.Add("required_string_group", parameterToString(requiredStringGroup, ""))
+	localVarQueryParams.Add("required_int64_group", parameterToString(requiredInt64Group, ""))
 	if localVarOptionals != nil && localVarOptionals.StringGroup.IsSet() {
 		localVarQueryParams.Add("string_group", parameterToString(localVarOptionals.StringGroup.Value(), ""))
 	}
@@ -965,6 +970,7 @@ func (a *FakeApiService) TestGroupParameters(ctx context.Context, localVarOption
 	if localVarHttpHeaderAccept != "" {
 		localVarHeaderParams["Accept"] = localVarHttpHeaderAccept
 	}
+	localVarHeaderParams["required_boolean_group"] = parameterToString(requiredBooleanGroup, "")
 	if localVarOptionals != nil && localVarOptionals.BooleanGroup.IsSet() {
 		localVarHeaderParams["boolean_group"] = parameterToString(localVarOptionals.BooleanGroup.Value(), "")
 	}
diff --git a/samples/client/petstore/go/go-petstore/docs/FakeApi.md b/samples/client/petstore/go/go-petstore/docs/FakeApi.md
index 8490ca254c7..c08f5d6f714 100644
--- a/samples/client/petstore/go/go-petstore/docs/FakeApi.md
+++ b/samples/client/petstore/go/go-petstore/docs/FakeApi.md
@@ -336,7 +336,7 @@ No authorization required
 [[Back to top]](#) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to Model list]](../README.md#documentation-for-models) [[Back to README]](../README.md)
 
 # **TestGroupParameters**
-> TestGroupParameters(ctx, optional)
+> TestGroupParameters(ctx, requiredStringGroup, requiredBooleanGroup, requiredInt64Group, optional)
 Fake endpoint to test group parameters (optional)
 
 Fake endpoint to test group parameters (optional)
@@ -346,6 +346,9 @@ Fake endpoint to test group parameters (optional)
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
  **ctx** | **context.Context** | context for authentication, logging, cancellation, deadlines, tracing, etc.
+  **requiredStringGroup** | **int32**| Required String in group parameters | 
+  **requiredBooleanGroup** | **bool**| Required Boolean in group parameters | 
+  **requiredInt64Group** | **int64**| Required Integer in group parameters | 
  **optional** | ***TestGroupParametersOpts** | optional parameters | nil if no parameters
 
 ### Optional Parameters
@@ -353,6 +356,9 @@ Optional parameters are passed through a pointer to a TestGroupParametersOpts st
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+
+
+
  **stringGroup** | **optional.Int32**| String in group parameters | 
  **booleanGroup** | **optional.Bool**| Boolean in group parameters | 
  **int64Group** | **optional.Int64**| Integer in group parameters | 
diff --git a/samples/client/petstore/haskell-http-client/lib/OpenAPIPetstore/API/Fake.hs b/samples/client/petstore/haskell-http-client/lib/OpenAPIPetstore/API/Fake.hs
index 0af6e0fa70e..03b15031c2c 100644
--- a/samples/client/petstore/haskell-http-client/lib/OpenAPIPetstore/API/Fake.hs
+++ b/samples/client/petstore/haskell-http-client/lib/OpenAPIPetstore/API/Fake.hs
@@ -377,9 +377,15 @@ instance Produces TestEnumParameters MimeNoContent
 -- Fake endpoint to test group parameters (optional)
 -- 
 testGroupParameters 
-  :: OpenAPIPetstoreRequest TestGroupParameters MimeNoContent NoContent MimeNoContent
-testGroupParameters =
+  :: RequiredStringGroup -- ^ "requiredStringGroup" -  Required String in group parameters
+  -> RequiredBooleanGroup -- ^ "requiredBooleanGroup" -  Required Boolean in group parameters
+  -> RequiredInt64Group -- ^ "requiredInt64Group" -  Required Integer in group parameters
+  -> OpenAPIPetstoreRequest TestGroupParameters MimeNoContent NoContent MimeNoContent
+testGroupParameters (RequiredStringGroup requiredStringGroup) (RequiredBooleanGroup requiredBooleanGroup) (RequiredInt64Group requiredInt64Group) =
   _mkRequest "DELETE" ["/fake"]
+    `setQuery` toQuery ("required_string_group", Just requiredStringGroup)
+    `setHeader` toHeader ("required_boolean_group", requiredBooleanGroup)
+    `setQuery` toQuery ("required_int64_group", Just requiredInt64Group)
 
 data TestGroupParameters  
 
diff --git a/samples/client/petstore/haskell-http-client/lib/OpenAPIPetstore/Model.hs b/samples/client/petstore/haskell-http-client/lib/OpenAPIPetstore/Model.hs
index d6a12c9dc75..ef55290920b 100644
--- a/samples/client/petstore/haskell-http-client/lib/OpenAPIPetstore/Model.hs
+++ b/samples/client/petstore/haskell-http-client/lib/OpenAPIPetstore/Model.hs
@@ -180,9 +180,18 @@ newtype Query = Query { unQuery :: Text } deriving (P.Eq, P.Show)
 -- ** RequestBody
 newtype RequestBody = RequestBody { unRequestBody :: (Map.Map String Text) } deriving (P.Eq, P.Show, A.ToJSON)
 
+-- ** RequiredBooleanGroup
+newtype RequiredBooleanGroup = RequiredBooleanGroup { unRequiredBooleanGroup :: Bool } deriving (P.Eq, P.Show)
+
 -- ** RequiredFile
 newtype RequiredFile = RequiredFile { unRequiredFile :: FilePath } deriving (P.Eq, P.Show)
 
+-- ** RequiredInt64Group
+newtype RequiredInt64Group = RequiredInt64Group { unRequiredInt64Group :: Integer } deriving (P.Eq, P.Show)
+
+-- ** RequiredStringGroup
+newtype RequiredStringGroup = RequiredStringGroup { unRequiredStringGroup :: Int } deriving (P.Eq, P.Show)
+
 -- ** Status
 newtype Status = Status { unStatus :: [E'Status2] } deriving (P.Eq, P.Show)
 
diff --git a/samples/client/petstore/haskell-http-client/openapi.yaml b/samples/client/petstore/haskell-http-client/openapi.yaml
index 95a925396fa..40878d2c58d 100644
--- a/samples/client/petstore/haskell-http-client/openapi.yaml
+++ b/samples/client/petstore/haskell-http-client/openapi.yaml
@@ -593,6 +593,25 @@ paths:
       description: Fake endpoint to test group parameters (optional)
       operationId: testGroupParameters
       parameters:
+      - description: Required String in group parameters
+        in: query
+        name: required_string_group
+        required: true
+        schema:
+          type: integer
+      - description: Required Boolean in group parameters
+        in: header
+        name: required_boolean_group
+        required: true
+        schema:
+          type: boolean
+      - description: Required Integer in group parameters
+        in: query
+        name: required_int64_group
+        required: true
+        schema:
+          format: int64
+          type: integer
       - description: String in group parameters
         in: query
         name: string_group
diff --git a/samples/client/petstore/java/feign/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/feign/src/main/java/org/openapitools/client/api/FakeApi.java
index af078f73628..e5bcaac7afe 100644
--- a/samples/client/petstore/java/feign/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/feign/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -249,16 +249,21 @@ public interface FakeApi extends ApiClient.Api {
   /**
    * Fake endpoint to test group parameters (optional)
    * Fake endpoint to test group parameters (optional)
+   * @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)
    */
-  @RequestLine("DELETE /fake?string_group={stringGroup}&int64_group={int64Group}")
+  @RequestLine("DELETE /fake?required_string_group={requiredStringGroup}&required_int64_group={requiredInt64Group}&string_group={stringGroup}&int64_group={int64Group}")
   @Headers({
     "Accept: application/json",
+    "required_boolean_group: {requiredBooleanGroup}",
+    
     "boolean_group: {booleanGroup}"
   })
-  void testGroupParameters(@Param("stringGroup") Integer stringGroup, @Param("booleanGroup") Boolean booleanGroup, @Param("int64Group") Long int64Group);
+  void testGroupParameters(@Param("requiredStringGroup") Integer requiredStringGroup, @Param("requiredBooleanGroup") Boolean requiredBooleanGroup, @Param("requiredInt64Group") Long requiredInt64Group, @Param("stringGroup") Integer stringGroup, @Param("booleanGroup") Boolean booleanGroup, @Param("int64Group") Long int64Group);
 
   /**
    * Fake endpoint to test group parameters (optional)
@@ -268,26 +273,39 @@ public interface FakeApi extends ApiClient.Api {
    * is convenient for services with optional query parameters, especially when
    * used with the {@link TestGroupParametersQueryParams} class that allows for
    * building up this map in a fluent style.
+   * @param requiredBooleanGroup Required Boolean in group parameters (required)
    * @param booleanGroup Boolean in group parameters (optional)
    * @param queryParams Map of query parameters as name-value pairs
    *   <p>The following elements may be specified in the query map:</p>
    *   <ul>
+   *   <li>requiredStringGroup - Required String in group parameters (required)</li>
+   *   <li>requiredInt64Group - Required Integer in group parameters (required)</li>
    *   <li>stringGroup - String in group parameters (optional)</li>
    *   <li>int64Group - Integer in group parameters (optional)</li>
    *   </ul>
    */
-  @RequestLine("DELETE /fake?string_group={stringGroup}&int64_group={int64Group}")
+  @RequestLine("DELETE /fake?required_string_group={requiredStringGroup}&required_int64_group={requiredInt64Group}&string_group={stringGroup}&int64_group={int64Group}")
   @Headers({
   "Accept: application/json",
+      "required_boolean_group: {requiredBooleanGroup}",
+      
       "boolean_group: {booleanGroup}"
   })
-  void testGroupParameters(@Param("booleanGroup") Boolean booleanGroup, @QueryMap(encoded=true) Map<String, Object> queryParams);
+  void testGroupParameters(@Param("requiredBooleanGroup") Boolean requiredBooleanGroup, @Param("booleanGroup") Boolean booleanGroup, @QueryMap(encoded=true) Map<String, Object> queryParams);
 
   /**
    * A convenience class for generating query parameters for the
    * <code>testGroupParameters</code> method in a fluent style.
    */
   public static class TestGroupParametersQueryParams extends HashMap<String, Object> {
+    public TestGroupParametersQueryParams requiredStringGroup(final Integer value) {
+      put("required_string_group", EncodingUtils.encode(value));
+      return this;
+    }
+    public TestGroupParametersQueryParams requiredInt64Group(final Long value) {
+      put("required_int64_group", EncodingUtils.encode(value));
+      return this;
+    }
     public TestGroupParametersQueryParams stringGroup(final Integer value) {
       put("string_group", EncodingUtils.encode(value));
       return this;
diff --git a/samples/client/petstore/java/feign/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/feign/src/test/java/org/openapitools/client/api/FakeApiTest.java
index 1203f5b63bd..bbb4a9bbc85 100644
--- a/samples/client/petstore/java/feign/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/feign/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -4,6 +4,7 @@ import org.openapitools.client.ApiClient;
 import java.math.BigDecimal;
 import org.openapitools.client.model.Client;
 import java.io.File;
+import org.openapitools.client.model.FileSchemaTestClass;
 import org.threeten.bp.LocalDate;
 import org.threeten.bp.OffsetDateTime;
 import org.openapitools.client.model.OuterComposite;
@@ -85,6 +86,20 @@ public class FakeApiTest {
     }
 
     
+    /**
+     * 
+     *
+     * For this test, the body for this request much reference a schema named &#x60;File&#x60;.
+     */
+    @Test
+    public void testBodyWithFileSchemaTest() {
+        FileSchemaTestClass fileSchemaTestClass = null;
+        // api.testBodyWithFileSchema(fileSchemaTestClass);
+
+        // TODO: test validations
+    }
+
+    
     /**
      * 
      *
@@ -202,6 +217,46 @@ public class FakeApiTest {
     // TODO: test validations
     }
     
+    /**
+     * Fake endpoint to test group parameters (optional)
+     *
+     * Fake endpoint to test group parameters (optional)
+     */
+    @Test
+    public void testGroupParametersTest() {
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
+        Integer stringGroup = null;
+        Boolean booleanGroup = null;
+        Long int64Group = null;
+        // api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
+
+        // TODO: test validations
+    }
+
+    /**
+     * Fake endpoint to test group parameters (optional)
+     *
+     * Fake endpoint to test group parameters (optional)
+     *
+     * This tests the overload of the method that uses a Map for query parameters instead of
+     * listing them out individually.
+     */
+    @Test
+    public void testGroupParametersTestQueryMap() {
+        Boolean requiredBooleanGroup = null;
+        Boolean booleanGroup = null;
+        FakeApi.TestGroupParametersQueryParams queryParams = new FakeApi.TestGroupParametersQueryParams()
+            .requiredStringGroup(null)
+            .requiredInt64Group(null)
+            .stringGroup(null)
+            .int64Group(null);
+        // api.testGroupParameters(requiredBooleanGroup, booleanGroup, queryParams);
+
+    // TODO: test validations
+    }
+    
     /**
      * test inline additionalProperties
      *
diff --git a/samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/api/FakeApi.java
index af078f73628..e5bcaac7afe 100644
--- a/samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/feign10x/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -249,16 +249,21 @@ public interface FakeApi extends ApiClient.Api {
   /**
    * Fake endpoint to test group parameters (optional)
    * Fake endpoint to test group parameters (optional)
+   * @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)
    */
-  @RequestLine("DELETE /fake?string_group={stringGroup}&int64_group={int64Group}")
+  @RequestLine("DELETE /fake?required_string_group={requiredStringGroup}&required_int64_group={requiredInt64Group}&string_group={stringGroup}&int64_group={int64Group}")
   @Headers({
     "Accept: application/json",
+    "required_boolean_group: {requiredBooleanGroup}",
+    
     "boolean_group: {booleanGroup}"
   })
-  void testGroupParameters(@Param("stringGroup") Integer stringGroup, @Param("booleanGroup") Boolean booleanGroup, @Param("int64Group") Long int64Group);
+  void testGroupParameters(@Param("requiredStringGroup") Integer requiredStringGroup, @Param("requiredBooleanGroup") Boolean requiredBooleanGroup, @Param("requiredInt64Group") Long requiredInt64Group, @Param("stringGroup") Integer stringGroup, @Param("booleanGroup") Boolean booleanGroup, @Param("int64Group") Long int64Group);
 
   /**
    * Fake endpoint to test group parameters (optional)
@@ -268,26 +273,39 @@ public interface FakeApi extends ApiClient.Api {
    * is convenient for services with optional query parameters, especially when
    * used with the {@link TestGroupParametersQueryParams} class that allows for
    * building up this map in a fluent style.
+   * @param requiredBooleanGroup Required Boolean in group parameters (required)
    * @param booleanGroup Boolean in group parameters (optional)
    * @param queryParams Map of query parameters as name-value pairs
    *   <p>The following elements may be specified in the query map:</p>
    *   <ul>
+   *   <li>requiredStringGroup - Required String in group parameters (required)</li>
+   *   <li>requiredInt64Group - Required Integer in group parameters (required)</li>
    *   <li>stringGroup - String in group parameters (optional)</li>
    *   <li>int64Group - Integer in group parameters (optional)</li>
    *   </ul>
    */
-  @RequestLine("DELETE /fake?string_group={stringGroup}&int64_group={int64Group}")
+  @RequestLine("DELETE /fake?required_string_group={requiredStringGroup}&required_int64_group={requiredInt64Group}&string_group={stringGroup}&int64_group={int64Group}")
   @Headers({
   "Accept: application/json",
+      "required_boolean_group: {requiredBooleanGroup}",
+      
       "boolean_group: {booleanGroup}"
   })
-  void testGroupParameters(@Param("booleanGroup") Boolean booleanGroup, @QueryMap(encoded=true) Map<String, Object> queryParams);
+  void testGroupParameters(@Param("requiredBooleanGroup") Boolean requiredBooleanGroup, @Param("booleanGroup") Boolean booleanGroup, @QueryMap(encoded=true) Map<String, Object> queryParams);
 
   /**
    * A convenience class for generating query parameters for the
    * <code>testGroupParameters</code> method in a fluent style.
    */
   public static class TestGroupParametersQueryParams extends HashMap<String, Object> {
+    public TestGroupParametersQueryParams requiredStringGroup(final Integer value) {
+      put("required_string_group", EncodingUtils.encode(value));
+      return this;
+    }
+    public TestGroupParametersQueryParams requiredInt64Group(final Long value) {
+      put("required_int64_group", EncodingUtils.encode(value));
+      return this;
+    }
     public TestGroupParametersQueryParams stringGroup(final Integer value) {
       put("string_group", EncodingUtils.encode(value));
       return this;
diff --git a/samples/client/petstore/java/feign10x/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/feign10x/src/test/java/org/openapitools/client/api/FakeApiTest.java
index c5153830112..bbb4a9bbc85 100644
--- a/samples/client/petstore/java/feign10x/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/feign10x/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -217,6 +217,46 @@ public class FakeApiTest {
     // TODO: test validations
     }
     
+    /**
+     * Fake endpoint to test group parameters (optional)
+     *
+     * Fake endpoint to test group parameters (optional)
+     */
+    @Test
+    public void testGroupParametersTest() {
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
+        Integer stringGroup = null;
+        Boolean booleanGroup = null;
+        Long int64Group = null;
+        // api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
+
+        // TODO: test validations
+    }
+
+    /**
+     * Fake endpoint to test group parameters (optional)
+     *
+     * Fake endpoint to test group parameters (optional)
+     *
+     * This tests the overload of the method that uses a Map for query parameters instead of
+     * listing them out individually.
+     */
+    @Test
+    public void testGroupParametersTestQueryMap() {
+        Boolean requiredBooleanGroup = null;
+        Boolean booleanGroup = null;
+        FakeApi.TestGroupParametersQueryParams queryParams = new FakeApi.TestGroupParametersQueryParams()
+            .requiredStringGroup(null)
+            .requiredInt64Group(null)
+            .stringGroup(null)
+            .int64Group(null);
+        // api.testGroupParameters(requiredBooleanGroup, booleanGroup, queryParams);
+
+    // TODO: test validations
+    }
+    
     /**
      * test inline additionalProperties
      *
diff --git a/samples/client/petstore/java/google-api-client/docs/FakeApi.md b/samples/client/petstore/java/google-api-client/docs/FakeApi.md
index a29ac9987a3..62046473c1f 100644
--- a/samples/client/petstore/java/google-api-client/docs/FakeApi.md
+++ b/samples/client/petstore/java/google-api-client/docs/FakeApi.md
@@ -470,7 +470,7 @@ No authorization required
 
 <a name="testGroupParameters"></a>
 # **testGroupParameters**
-> testGroupParameters(stringGroup, booleanGroup, int64Group)
+> testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group)
 
 Fake endpoint to test group parameters (optional)
 
@@ -484,11 +484,14 @@ Fake endpoint to test group parameters (optional)
 
 
 FakeApi apiInstance = new FakeApi();
+Integer requiredStringGroup = 56; // Integer | Required String in group parameters
+Boolean requiredBooleanGroup = true; // Boolean | Required Boolean in group parameters
+Long requiredInt64Group = 56L; // Long | Required Integer in group parameters
 Integer stringGroup = 56; // Integer | String in group parameters
 Boolean booleanGroup = true; // Boolean | Boolean in group parameters
 Long int64Group = 56L; // Long | Integer in group parameters
 try {
-    apiInstance.testGroupParameters(stringGroup, booleanGroup, int64Group);
+    apiInstance.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 } catch (ApiException e) {
     System.err.println("Exception when calling FakeApi#testGroupParameters");
     e.printStackTrace();
@@ -499,6 +502,9 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **requiredStringGroup** | **Integer**| Required String in group parameters |
+ **requiredBooleanGroup** | **Boolean**| Required Boolean in group parameters |
+ **requiredInt64Group** | **Long**| Required Integer in group parameters |
  **stringGroup** | **Integer**| String in group parameters | [optional]
  **booleanGroup** | **Boolean**| Boolean in group parameters | [optional]
  **int64Group** | **Long**| Integer in group parameters | [optional]
diff --git a/samples/client/petstore/java/google-api-client/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/google-api-client/src/main/java/org/openapitools/client/api/FakeApi.java
index 706f7ac9a5d..90a90a5f13c 100644
--- a/samples/client/petstore/java/google-api-client/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/google-api-client/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -883,30 +883,65 @@ public class FakeApi {
     * 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
     * @throws IOException if an error occurs while attempting to invoke the API
     **/
-    public void testGroupParameters(Integer stringGroup, Boolean booleanGroup, Long int64Group) throws IOException {
-        testGroupParametersForHttpResponse(stringGroup, booleanGroup, int64Group);
+    public void testGroupParameters(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws IOException {
+        testGroupParametersForHttpResponse(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
+    * @param requiredBooleanGroup Required Boolean in group parameters
+    * @param requiredInt64Group Required Integer in group parameters
     * @param params Map of query params. A collection will be interpreted as passing in multiple instances of the same query param.
     * @throws IOException if an error occurs while attempting to invoke the API
     **/
-    public void testGroupParameters(Map<String, Object> params) throws IOException {
-        testGroupParametersForHttpResponse(params);
+    public void testGroupParameters(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Map<String, Object> params) throws IOException {
+        testGroupParametersForHttpResponse(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, params);
     }
 
-    public HttpResponse testGroupParametersForHttpResponse(Integer stringGroup, Boolean booleanGroup, Long int64Group) throws IOException {
-        
+    public HttpResponse testGroupParametersForHttpResponse(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws IOException {
+        // verify the required parameter 'requiredStringGroup' is set
+        if (requiredStringGroup == null) {
+            throw new IllegalArgumentException("Missing the required parameter 'requiredStringGroup' when calling testGroupParameters");
+        }// verify the required parameter 'requiredBooleanGroup' is set
+        if (requiredBooleanGroup == null) {
+            throw new IllegalArgumentException("Missing the required parameter 'requiredBooleanGroup' when calling testGroupParameters");
+        }// verify the required parameter 'requiredInt64Group' is set
+        if (requiredInt64Group == null) {
+            throw new IllegalArgumentException("Missing the required parameter 'requiredInt64Group' when calling testGroupParameters");
+        }
         UriBuilder uriBuilder = UriBuilder.fromUri(apiClient.getBasePath() + "/fake");
-        if (stringGroup != null) {
+        if (requiredStringGroup != null) {
+            String key = "required_string_group";
+            Object value = requiredStringGroup;
+            if (value instanceof Collection) {
+                uriBuilder = uriBuilder.queryParam(key, ((Collection) value).toArray());
+            } else if (value instanceof Object[]) {
+                uriBuilder = uriBuilder.queryParam(key, (Object[]) value);
+            } else {
+                uriBuilder = uriBuilder.queryParam(key, value);
+            }
+        }        if (requiredInt64Group != null) {
+            String key = "required_int64_group";
+            Object value = requiredInt64Group;
+            if (value instanceof Collection) {
+                uriBuilder = uriBuilder.queryParam(key, ((Collection) value).toArray());
+            } else if (value instanceof Object[]) {
+                uriBuilder = uriBuilder.queryParam(key, (Object[]) value);
+            } else {
+                uriBuilder = uriBuilder.queryParam(key, value);
+            }
+        }        if (stringGroup != null) {
             String key = "string_group";
             Object value = stringGroup;
             if (value instanceof Collection) {
@@ -935,12 +970,25 @@ public class FakeApi {
         return apiClient.getHttpRequestFactory().buildRequest(HttpMethods.DELETE, genericUrl, content).execute();
     }
 
-    public HttpResponse testGroupParametersForHttpResponse(Map<String, Object> params) throws IOException {
-        
+    public HttpResponse testGroupParametersForHttpResponse(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Map<String, Object> params) throws IOException {
+        // verify the required parameter 'requiredStringGroup' is set
+        if (requiredStringGroup == null) {
+            throw new IllegalArgumentException("Missing the required parameter 'requiredStringGroup' when calling testGroupParameters");
+        }// verify the required parameter 'requiredBooleanGroup' is set
+        if (requiredBooleanGroup == null) {
+            throw new IllegalArgumentException("Missing the required parameter 'requiredBooleanGroup' when calling testGroupParameters");
+        }// verify the required parameter 'requiredInt64Group' is set
+        if (requiredInt64Group == null) {
+            throw new IllegalArgumentException("Missing the required parameter 'requiredInt64Group' when calling testGroupParameters");
+        }
         UriBuilder uriBuilder = UriBuilder.fromUri(apiClient.getBasePath() + "/fake");
 
         // Copy the params argument if present, to allow passing in immutable maps
         Map<String, Object> allParams = params == null ? new HashMap<String, Object>() : new HashMap<String, Object>(params);
+        // Add the required query param 'requiredStringGroup' to the map of query params
+        allParams.put("requiredStringGroup", requiredStringGroup);
+        // Add the required query param 'requiredInt64Group' to the map of query params
+        allParams.put("requiredInt64Group", requiredInt64Group);
 
         for (Map.Entry<String, Object> entry: allParams.entrySet()) {
             String key = entry.getKey();
diff --git a/samples/client/petstore/java/google-api-client/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/google-api-client/src/test/java/org/openapitools/client/api/FakeApiTest.java
index 17250f43361..d8bfb243b10 100644
--- a/samples/client/petstore/java/google-api-client/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/google-api-client/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -16,6 +16,7 @@ package org.openapitools.client.api;
 import java.math.BigDecimal;
 import org.openapitools.client.model.Client;
 import java.io.File;
+import org.openapitools.client.model.FileSchemaTestClass;
 import org.threeten.bp.LocalDate;
 import org.threeten.bp.OffsetDateTime;
 import org.openapitools.client.model.OuterComposite;
@@ -102,6 +103,22 @@ public class FakeApiTest {
         // TODO: test validations
     }
     
+    /**
+     * 
+     *
+     * For this test, the body for this request much reference a schema named &#x60;File&#x60;.
+     *
+     * @throws IOException
+     *          if the Api call fails
+     */
+    @Test
+    public void testBodyWithFileSchemaTest() throws IOException {
+        FileSchemaTestClass fileSchemaTestClass = null;
+        api.testBodyWithFileSchema(fileSchemaTestClass);
+
+        // TODO: test validations
+    }
+    
     /**
      * 
      *
@@ -187,6 +204,27 @@ public class FakeApiTest {
         // TODO: test validations
     }
     
+    /**
+     * Fake endpoint to test group parameters (optional)
+     *
+     * Fake endpoint to test group parameters (optional)
+     *
+     * @throws IOException
+     *          if the Api call fails
+     */
+    @Test
+    public void testGroupParametersTest() throws IOException {
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
+        Integer stringGroup = null;
+        Boolean booleanGroup = null;
+        Long int64Group = null;
+        api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
+
+        // TODO: test validations
+    }
+    
     /**
      * test inline additionalProperties
      *
diff --git a/samples/client/petstore/java/jersey1/docs/FakeApi.md b/samples/client/petstore/java/jersey1/docs/FakeApi.md
index a29ac9987a3..62046473c1f 100644
--- a/samples/client/petstore/java/jersey1/docs/FakeApi.md
+++ b/samples/client/petstore/java/jersey1/docs/FakeApi.md
@@ -470,7 +470,7 @@ No authorization required
 
 <a name="testGroupParameters"></a>
 # **testGroupParameters**
-> testGroupParameters(stringGroup, booleanGroup, int64Group)
+> testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group)
 
 Fake endpoint to test group parameters (optional)
 
@@ -484,11 +484,14 @@ Fake endpoint to test group parameters (optional)
 
 
 FakeApi apiInstance = new FakeApi();
+Integer requiredStringGroup = 56; // Integer | Required String in group parameters
+Boolean requiredBooleanGroup = true; // Boolean | Required Boolean in group parameters
+Long requiredInt64Group = 56L; // Long | Required Integer in group parameters
 Integer stringGroup = 56; // Integer | String in group parameters
 Boolean booleanGroup = true; // Boolean | Boolean in group parameters
 Long int64Group = 56L; // Long | Integer in group parameters
 try {
-    apiInstance.testGroupParameters(stringGroup, booleanGroup, int64Group);
+    apiInstance.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 } catch (ApiException e) {
     System.err.println("Exception when calling FakeApi#testGroupParameters");
     e.printStackTrace();
@@ -499,6 +502,9 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **requiredStringGroup** | **Integer**| Required String in group parameters |
+ **requiredBooleanGroup** | **Boolean**| Required Boolean in group parameters |
+ **requiredInt64Group** | **Long**| Required Integer in group parameters |
  **stringGroup** | **Integer**| String in group parameters | [optional]
  **booleanGroup** | **Boolean**| Boolean in group parameters | [optional]
  **int64Group** | **Long**| Integer in group parameters | [optional]
diff --git a/samples/client/petstore/java/jersey1/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/jersey1/src/main/java/org/openapitools/client/api/FakeApi.java
index 97fe4cc1356..f4f7e114907 100644
--- a/samples/client/petstore/java/jersey1/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/jersey1/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -489,14 +489,32 @@ if (enumFormString != null)
   /**
    * Fake endpoint to test group parameters (optional)
    * Fake endpoint to test group parameters (optional)
+   * @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 ApiException if fails to make API call
    */
-  public void testGroupParameters(Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
+  public void testGroupParameters(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
     Object localVarPostBody = null;
     
+    // verify the required parameter 'requiredStringGroup' is set
+    if (requiredStringGroup == null) {
+      throw new ApiException(400, "Missing the required parameter 'requiredStringGroup' when calling testGroupParameters");
+    }
+    
+    // verify the required parameter 'requiredBooleanGroup' is set
+    if (requiredBooleanGroup == null) {
+      throw new ApiException(400, "Missing the required parameter 'requiredBooleanGroup' when calling testGroupParameters");
+    }
+    
+    // verify the required parameter 'requiredInt64Group' is set
+    if (requiredInt64Group == null) {
+      throw new ApiException(400, "Missing the required parameter 'requiredInt64Group' when calling testGroupParameters");
+    }
+    
     // create path and map variables
     String localVarPath = "/fake";
 
@@ -506,10 +524,14 @@ if (enumFormString != null)
     Map<String, String> localVarHeaderParams = new HashMap<String, String>();
     Map<String, Object> localVarFormParams = new HashMap<String, Object>();
 
+    localVarQueryParams.addAll(apiClient.parameterToPair("required_string_group", requiredStringGroup));
+    localVarQueryParams.addAll(apiClient.parameterToPair("required_int64_group", requiredInt64Group));
     localVarQueryParams.addAll(apiClient.parameterToPair("string_group", stringGroup));
     localVarQueryParams.addAll(apiClient.parameterToPair("int64_group", int64Group));
 
-    if (booleanGroup != null)
+    if (requiredBooleanGroup != null)
+      localVarHeaderParams.put("required_boolean_group", apiClient.parameterToString(requiredBooleanGroup));
+if (booleanGroup != null)
       localVarHeaderParams.put("boolean_group", apiClient.parameterToString(booleanGroup));
 
     
diff --git a/samples/client/petstore/java/jersey1/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/jersey1/src/test/java/org/openapitools/client/api/FakeApiTest.java
index 23f854df6ab..07f4a80a5b2 100644
--- a/samples/client/petstore/java/jersey1/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/jersey1/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -15,6 +15,7 @@ package org.openapitools.client.api;
 
 import org.openapitools.client.ApiException;
 import java.math.BigDecimal;
+import org.openapitools.client.model.Client;
 import java.io.File;
 import org.openapitools.client.model.FileSchemaTestClass;
 import org.threeten.bp.LocalDate;
@@ -135,6 +136,22 @@ public class FakeApiTest {
         // TODO: test validations
     }
     
+    /**
+     * To test \&quot;client\&quot; model
+     *
+     * To test \&quot;client\&quot; model
+     *
+     * @throws ApiException
+     *          if the Api call fails
+     */
+    @Test
+    public void testClientModelTest() throws ApiException {
+        Client client = null;
+        Client response = api.testClientModel(client);
+
+        // TODO: test validations
+    }
+    
     /**
      * Fake endpoint for testing various parameters 假端點 偽のエンドポイント 가짜 엔드 포인트 
      *
@@ -197,10 +214,13 @@ public class FakeApiTest {
      */
     @Test
     public void testGroupParametersTest() throws ApiException {
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
         Integer stringGroup = null;
         Boolean booleanGroup = null;
         Long int64Group = null;
-        api.testGroupParameters(stringGroup, booleanGroup, int64Group);
+        api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 
         // TODO: test validations
     }
diff --git a/samples/client/petstore/java/jersey2-java6/docs/FakeApi.md b/samples/client/petstore/java/jersey2-java6/docs/FakeApi.md
index a29ac9987a3..62046473c1f 100644
--- a/samples/client/petstore/java/jersey2-java6/docs/FakeApi.md
+++ b/samples/client/petstore/java/jersey2-java6/docs/FakeApi.md
@@ -470,7 +470,7 @@ No authorization required
 
 <a name="testGroupParameters"></a>
 # **testGroupParameters**
-> testGroupParameters(stringGroup, booleanGroup, int64Group)
+> testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group)
 
 Fake endpoint to test group parameters (optional)
 
@@ -484,11 +484,14 @@ Fake endpoint to test group parameters (optional)
 
 
 FakeApi apiInstance = new FakeApi();
+Integer requiredStringGroup = 56; // Integer | Required String in group parameters
+Boolean requiredBooleanGroup = true; // Boolean | Required Boolean in group parameters
+Long requiredInt64Group = 56L; // Long | Required Integer in group parameters
 Integer stringGroup = 56; // Integer | String in group parameters
 Boolean booleanGroup = true; // Boolean | Boolean in group parameters
 Long int64Group = 56L; // Long | Integer in group parameters
 try {
-    apiInstance.testGroupParameters(stringGroup, booleanGroup, int64Group);
+    apiInstance.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 } catch (ApiException e) {
     System.err.println("Exception when calling FakeApi#testGroupParameters");
     e.printStackTrace();
@@ -499,6 +502,9 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **requiredStringGroup** | **Integer**| Required String in group parameters |
+ **requiredBooleanGroup** | **Boolean**| Required Boolean in group parameters |
+ **requiredInt64Group** | **Long**| Required Integer in group parameters |
  **stringGroup** | **Integer**| String in group parameters | [optional]
  **booleanGroup** | **Boolean**| Boolean in group parameters | [optional]
  **int64Group** | **Long**| Integer in group parameters | [optional]
diff --git a/samples/client/petstore/java/jersey2-java6/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/jersey2-java6/src/main/java/org/openapitools/client/api/FakeApi.java
index f27eb4d2d53..d167939bf5b 100644
--- a/samples/client/petstore/java/jersey2-java6/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/jersey2-java6/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -587,27 +587,48 @@ if (enumFormString != null)
   /**
    * Fake endpoint to test group parameters (optional)
    * Fake endpoint to test group parameters (optional)
+   * @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 ApiException if fails to make API call
    */
-  public void testGroupParameters(Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
+  public void testGroupParameters(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
 
-    testGroupParametersWithHttpInfo(stringGroup, booleanGroup, int64Group);
+    testGroupParametersWithHttpInfo(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
   }
 
   /**
    * Fake endpoint to test group parameters (optional)
    * Fake endpoint to test group parameters (optional)
+   * @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 ApiException if fails to make API call
    */
-  public ApiResponse<Void> testGroupParametersWithHttpInfo(Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
+  public ApiResponse<Void> testGroupParametersWithHttpInfo(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
     Object localVarPostBody = new Object();
     
+    // verify the required parameter 'requiredStringGroup' is set
+    if (requiredStringGroup == null) {
+      throw new ApiException(400, "Missing the required parameter 'requiredStringGroup' when calling testGroupParameters");
+    }
+    
+    // verify the required parameter 'requiredBooleanGroup' is set
+    if (requiredBooleanGroup == null) {
+      throw new ApiException(400, "Missing the required parameter 'requiredBooleanGroup' when calling testGroupParameters");
+    }
+    
+    // verify the required parameter 'requiredInt64Group' is set
+    if (requiredInt64Group == null) {
+      throw new ApiException(400, "Missing the required parameter 'requiredInt64Group' when calling testGroupParameters");
+    }
+    
     // create path and map variables
     String localVarPath = "/fake";
 
@@ -616,10 +637,14 @@ if (enumFormString != null)
     Map<String, String> localVarHeaderParams = new HashMap<String, String>();
     Map<String, Object> localVarFormParams = new HashMap<String, Object>();
 
+    localVarQueryParams.addAll(apiClient.parameterToPairs("", "required_string_group", requiredStringGroup));
+    localVarQueryParams.addAll(apiClient.parameterToPairs("", "required_int64_group", requiredInt64Group));
     localVarQueryParams.addAll(apiClient.parameterToPairs("", "string_group", stringGroup));
     localVarQueryParams.addAll(apiClient.parameterToPairs("", "int64_group", int64Group));
 
-    if (booleanGroup != null)
+    if (requiredBooleanGroup != null)
+      localVarHeaderParams.put("required_boolean_group", apiClient.parameterToString(requiredBooleanGroup));
+if (booleanGroup != null)
       localVarHeaderParams.put("boolean_group", apiClient.parameterToString(booleanGroup));
 
     
diff --git a/samples/client/petstore/java/jersey2-java6/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/jersey2-java6/src/test/java/org/openapitools/client/api/FakeApiTest.java
index 11916028aac..07f4a80a5b2 100644
--- a/samples/client/petstore/java/jersey2-java6/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/jersey2-java6/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -204,6 +204,27 @@ public class FakeApiTest {
         // TODO: test validations
     }
     
+    /**
+     * Fake endpoint to test group parameters (optional)
+     *
+     * Fake endpoint to test group parameters (optional)
+     *
+     * @throws ApiException
+     *          if the Api call fails
+     */
+    @Test
+    public void testGroupParametersTest() throws ApiException {
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
+        Integer stringGroup = null;
+        Boolean booleanGroup = null;
+        Long int64Group = null;
+        api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
+
+        // TODO: test validations
+    }
+    
     /**
      * test inline additionalProperties
      *
diff --git a/samples/client/petstore/java/jersey2-java8/docs/FakeApi.md b/samples/client/petstore/java/jersey2-java8/docs/FakeApi.md
index a29ac9987a3..62046473c1f 100644
--- a/samples/client/petstore/java/jersey2-java8/docs/FakeApi.md
+++ b/samples/client/petstore/java/jersey2-java8/docs/FakeApi.md
@@ -470,7 +470,7 @@ No authorization required
 
 <a name="testGroupParameters"></a>
 # **testGroupParameters**
-> testGroupParameters(stringGroup, booleanGroup, int64Group)
+> testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group)
 
 Fake endpoint to test group parameters (optional)
 
@@ -484,11 +484,14 @@ Fake endpoint to test group parameters (optional)
 
 
 FakeApi apiInstance = new FakeApi();
+Integer requiredStringGroup = 56; // Integer | Required String in group parameters
+Boolean requiredBooleanGroup = true; // Boolean | Required Boolean in group parameters
+Long requiredInt64Group = 56L; // Long | Required Integer in group parameters
 Integer stringGroup = 56; // Integer | String in group parameters
 Boolean booleanGroup = true; // Boolean | Boolean in group parameters
 Long int64Group = 56L; // Long | Integer in group parameters
 try {
-    apiInstance.testGroupParameters(stringGroup, booleanGroup, int64Group);
+    apiInstance.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 } catch (ApiException e) {
     System.err.println("Exception when calling FakeApi#testGroupParameters");
     e.printStackTrace();
@@ -499,6 +502,9 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **requiredStringGroup** | **Integer**| Required String in group parameters |
+ **requiredBooleanGroup** | **Boolean**| Required Boolean in group parameters |
+ **requiredInt64Group** | **Long**| Required Integer in group parameters |
  **stringGroup** | **Integer**| String in group parameters | [optional]
  **booleanGroup** | **Boolean**| Boolean in group parameters | [optional]
  **int64Group** | **Long**| Integer in group parameters | [optional]
diff --git a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/FakeApi.java
index 434cebdd6f3..068ba3e71f7 100644
--- a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -587,27 +587,48 @@ if (enumFormString != null)
   /**
    * Fake endpoint to test group parameters (optional)
    * Fake endpoint to test group parameters (optional)
+   * @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 ApiException if fails to make API call
    */
-  public void testGroupParameters(Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
+  public void testGroupParameters(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
 
-    testGroupParametersWithHttpInfo(stringGroup, booleanGroup, int64Group);
+    testGroupParametersWithHttpInfo(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
   }
 
   /**
    * Fake endpoint to test group parameters (optional)
    * Fake endpoint to test group parameters (optional)
+   * @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 ApiException if fails to make API call
    */
-  public ApiResponse<Void> testGroupParametersWithHttpInfo(Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
+  public ApiResponse<Void> testGroupParametersWithHttpInfo(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
     Object localVarPostBody = new Object();
     
+    // verify the required parameter 'requiredStringGroup' is set
+    if (requiredStringGroup == null) {
+      throw new ApiException(400, "Missing the required parameter 'requiredStringGroup' when calling testGroupParameters");
+    }
+    
+    // verify the required parameter 'requiredBooleanGroup' is set
+    if (requiredBooleanGroup == null) {
+      throw new ApiException(400, "Missing the required parameter 'requiredBooleanGroup' when calling testGroupParameters");
+    }
+    
+    // verify the required parameter 'requiredInt64Group' is set
+    if (requiredInt64Group == null) {
+      throw new ApiException(400, "Missing the required parameter 'requiredInt64Group' when calling testGroupParameters");
+    }
+    
     // create path and map variables
     String localVarPath = "/fake";
 
@@ -616,10 +637,14 @@ if (enumFormString != null)
     Map<String, String> localVarHeaderParams = new HashMap<String, String>();
     Map<String, Object> localVarFormParams = new HashMap<String, Object>();
 
+    localVarQueryParams.addAll(apiClient.parameterToPairs("", "required_string_group", requiredStringGroup));
+    localVarQueryParams.addAll(apiClient.parameterToPairs("", "required_int64_group", requiredInt64Group));
     localVarQueryParams.addAll(apiClient.parameterToPairs("", "string_group", stringGroup));
     localVarQueryParams.addAll(apiClient.parameterToPairs("", "int64_group", int64Group));
 
-    if (booleanGroup != null)
+    if (requiredBooleanGroup != null)
+      localVarHeaderParams.put("required_boolean_group", apiClient.parameterToString(requiredBooleanGroup));
+if (booleanGroup != null)
       localVarHeaderParams.put("boolean_group", apiClient.parameterToString(booleanGroup));
 
     
diff --git a/samples/client/petstore/java/jersey2-java8/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/jersey2-java8/src/test/java/org/openapitools/client/api/FakeApiTest.java
index 66fd7294503..4731d235db3 100644
--- a/samples/client/petstore/java/jersey2-java8/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/jersey2-java8/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -214,10 +214,13 @@ public class FakeApiTest {
      */
     @Test
     public void testGroupParametersTest() throws ApiException {
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
         Integer stringGroup = null;
         Boolean booleanGroup = null;
         Long int64Group = null;
-        api.testGroupParameters(stringGroup, booleanGroup, int64Group);
+        api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 
         // TODO: test validations
     }
diff --git a/samples/client/petstore/java/jersey2/docs/FakeApi.md b/samples/client/petstore/java/jersey2/docs/FakeApi.md
index a29ac9987a3..62046473c1f 100644
--- a/samples/client/petstore/java/jersey2/docs/FakeApi.md
+++ b/samples/client/petstore/java/jersey2/docs/FakeApi.md
@@ -470,7 +470,7 @@ No authorization required
 
 <a name="testGroupParameters"></a>
 # **testGroupParameters**
-> testGroupParameters(stringGroup, booleanGroup, int64Group)
+> testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group)
 
 Fake endpoint to test group parameters (optional)
 
@@ -484,11 +484,14 @@ Fake endpoint to test group parameters (optional)
 
 
 FakeApi apiInstance = new FakeApi();
+Integer requiredStringGroup = 56; // Integer | Required String in group parameters
+Boolean requiredBooleanGroup = true; // Boolean | Required Boolean in group parameters
+Long requiredInt64Group = 56L; // Long | Required Integer in group parameters
 Integer stringGroup = 56; // Integer | String in group parameters
 Boolean booleanGroup = true; // Boolean | Boolean in group parameters
 Long int64Group = 56L; // Long | Integer in group parameters
 try {
-    apiInstance.testGroupParameters(stringGroup, booleanGroup, int64Group);
+    apiInstance.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 } catch (ApiException e) {
     System.err.println("Exception when calling FakeApi#testGroupParameters");
     e.printStackTrace();
@@ -499,6 +502,9 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **requiredStringGroup** | **Integer**| Required String in group parameters |
+ **requiredBooleanGroup** | **Boolean**| Required Boolean in group parameters |
+ **requiredInt64Group** | **Long**| Required Integer in group parameters |
  **stringGroup** | **Integer**| String in group parameters | [optional]
  **booleanGroup** | **Boolean**| Boolean in group parameters | [optional]
  **int64Group** | **Long**| Integer in group parameters | [optional]
diff --git a/samples/client/petstore/java/jersey2/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/jersey2/src/main/java/org/openapitools/client/api/FakeApi.java
index f27eb4d2d53..d167939bf5b 100644
--- a/samples/client/petstore/java/jersey2/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/jersey2/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -587,27 +587,48 @@ if (enumFormString != null)
   /**
    * Fake endpoint to test group parameters (optional)
    * Fake endpoint to test group parameters (optional)
+   * @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 ApiException if fails to make API call
    */
-  public void testGroupParameters(Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
+  public void testGroupParameters(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
 
-    testGroupParametersWithHttpInfo(stringGroup, booleanGroup, int64Group);
+    testGroupParametersWithHttpInfo(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
   }
 
   /**
    * Fake endpoint to test group parameters (optional)
    * Fake endpoint to test group parameters (optional)
+   * @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 ApiException if fails to make API call
    */
-  public ApiResponse<Void> testGroupParametersWithHttpInfo(Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
+  public ApiResponse<Void> testGroupParametersWithHttpInfo(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
     Object localVarPostBody = new Object();
     
+    // verify the required parameter 'requiredStringGroup' is set
+    if (requiredStringGroup == null) {
+      throw new ApiException(400, "Missing the required parameter 'requiredStringGroup' when calling testGroupParameters");
+    }
+    
+    // verify the required parameter 'requiredBooleanGroup' is set
+    if (requiredBooleanGroup == null) {
+      throw new ApiException(400, "Missing the required parameter 'requiredBooleanGroup' when calling testGroupParameters");
+    }
+    
+    // verify the required parameter 'requiredInt64Group' is set
+    if (requiredInt64Group == null) {
+      throw new ApiException(400, "Missing the required parameter 'requiredInt64Group' when calling testGroupParameters");
+    }
+    
     // create path and map variables
     String localVarPath = "/fake";
 
@@ -616,10 +637,14 @@ if (enumFormString != null)
     Map<String, String> localVarHeaderParams = new HashMap<String, String>();
     Map<String, Object> localVarFormParams = new HashMap<String, Object>();
 
+    localVarQueryParams.addAll(apiClient.parameterToPairs("", "required_string_group", requiredStringGroup));
+    localVarQueryParams.addAll(apiClient.parameterToPairs("", "required_int64_group", requiredInt64Group));
     localVarQueryParams.addAll(apiClient.parameterToPairs("", "string_group", stringGroup));
     localVarQueryParams.addAll(apiClient.parameterToPairs("", "int64_group", int64Group));
 
-    if (booleanGroup != null)
+    if (requiredBooleanGroup != null)
+      localVarHeaderParams.put("required_boolean_group", apiClient.parameterToString(requiredBooleanGroup));
+if (booleanGroup != null)
       localVarHeaderParams.put("boolean_group", apiClient.parameterToString(booleanGroup));
 
     
diff --git a/samples/client/petstore/java/jersey2/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/jersey2/src/test/java/org/openapitools/client/api/FakeApiTest.java
index 6fffb218baa..07f4a80a5b2 100644
--- a/samples/client/petstore/java/jersey2/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/jersey2/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -214,10 +214,13 @@ public class FakeApiTest {
      */
     @Test
     public void testGroupParametersTest() throws ApiException {
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
         Integer stringGroup = null;
         Boolean booleanGroup = null;
         Long int64Group = null;
-        api.testGroupParameters(stringGroup, booleanGroup, int64Group);
+        api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 
         // TODO: test validations
     }
diff --git a/samples/client/petstore/java/okhttp-gson-parcelableModel/docs/FakeApi.md b/samples/client/petstore/java/okhttp-gson-parcelableModel/docs/FakeApi.md
index a29ac9987a3..62046473c1f 100644
--- a/samples/client/petstore/java/okhttp-gson-parcelableModel/docs/FakeApi.md
+++ b/samples/client/petstore/java/okhttp-gson-parcelableModel/docs/FakeApi.md
@@ -470,7 +470,7 @@ No authorization required
 
 <a name="testGroupParameters"></a>
 # **testGroupParameters**
-> testGroupParameters(stringGroup, booleanGroup, int64Group)
+> testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group)
 
 Fake endpoint to test group parameters (optional)
 
@@ -484,11 +484,14 @@ Fake endpoint to test group parameters (optional)
 
 
 FakeApi apiInstance = new FakeApi();
+Integer requiredStringGroup = 56; // Integer | Required String in group parameters
+Boolean requiredBooleanGroup = true; // Boolean | Required Boolean in group parameters
+Long requiredInt64Group = 56L; // Long | Required Integer in group parameters
 Integer stringGroup = 56; // Integer | String in group parameters
 Boolean booleanGroup = true; // Boolean | Boolean in group parameters
 Long int64Group = 56L; // Long | Integer in group parameters
 try {
-    apiInstance.testGroupParameters(stringGroup, booleanGroup, int64Group);
+    apiInstance.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 } catch (ApiException e) {
     System.err.println("Exception when calling FakeApi#testGroupParameters");
     e.printStackTrace();
@@ -499,6 +502,9 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **requiredStringGroup** | **Integer**| Required String in group parameters |
+ **requiredBooleanGroup** | **Boolean**| Required Boolean in group parameters |
+ **requiredInt64Group** | **Long**| Required Integer in group parameters |
  **stringGroup** | **Integer**| String in group parameters | [optional]
  **booleanGroup** | **Boolean**| Boolean in group parameters | [optional]
  **int64Group** | **Long**| Integer in group parameters | [optional]
diff --git a/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/api/FakeApi.java
index 783dfb78ec2..49f8a954e98 100644
--- a/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/okhttp-gson-parcelableModel/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -1307,6 +1307,9 @@ public class FakeApi {
     }
     /**
      * Build call for testGroupParameters
+     * @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)
@@ -1315,7 +1318,7 @@ public class FakeApi {
      * @return Call to execute
      * @throws ApiException If fail to serialize the request body object
      */
-    public com.squareup.okhttp.Call testGroupParametersCall(Integer stringGroup, Boolean booleanGroup, Long int64Group, final ProgressResponseBody.ProgressListener progressListener, final ProgressRequestBody.ProgressRequestListener progressRequestListener) throws ApiException {
+    public com.squareup.okhttp.Call testGroupParametersCall(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group, final ProgressResponseBody.ProgressListener progressListener, final ProgressRequestBody.ProgressRequestListener progressRequestListener) throws ApiException {
         Object localVarPostBody = new Object();
 
         // create path and map variables
@@ -1323,6 +1326,14 @@ public class FakeApi {
 
         List<Pair> localVarQueryParams = new ArrayList<Pair>();
         List<Pair> localVarCollectionQueryParams = new ArrayList<Pair>();
+        if (requiredStringGroup != null) {
+            localVarQueryParams.addAll(apiClient.parameterToPair("required_string_group", requiredStringGroup));
+        }
+
+        if (requiredInt64Group != null) {
+            localVarQueryParams.addAll(apiClient.parameterToPair("required_int64_group", requiredInt64Group));
+        }
+
         if (stringGroup != null) {
             localVarQueryParams.addAll(apiClient.parameterToPair("string_group", stringGroup));
         }
@@ -1332,6 +1343,10 @@ public class FakeApi {
         }
 
         Map<String, String> localVarHeaderParams = new HashMap<String, String>();
+        if (requiredBooleanGroup != null) {
+            localVarHeaderParams.put("required_boolean_group", apiClient.parameterToString(requiredBooleanGroup));
+        }
+
         if (booleanGroup != null) {
             localVarHeaderParams.put("boolean_group", apiClient.parameterToString(booleanGroup));
         }
@@ -1368,10 +1383,25 @@ public class FakeApi {
     }
 
     @SuppressWarnings("rawtypes")
-    private com.squareup.okhttp.Call testGroupParametersValidateBeforeCall(Integer stringGroup, Boolean booleanGroup, Long int64Group, final ProgressResponseBody.ProgressListener progressListener, final ProgressRequestBody.ProgressRequestListener progressRequestListener) throws ApiException {
+    private com.squareup.okhttp.Call testGroupParametersValidateBeforeCall(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group, final ProgressResponseBody.ProgressListener progressListener, final ProgressRequestBody.ProgressRequestListener progressRequestListener) throws ApiException {
+        
+        // verify the required parameter 'requiredStringGroup' is set
+        if (requiredStringGroup == null) {
+            throw new ApiException("Missing the required parameter 'requiredStringGroup' when calling testGroupParameters(Async)");
+        }
+        
+        // verify the required parameter 'requiredBooleanGroup' is set
+        if (requiredBooleanGroup == null) {
+            throw new ApiException("Missing the required parameter 'requiredBooleanGroup' when calling testGroupParameters(Async)");
+        }
+        
+        // verify the required parameter 'requiredInt64Group' is set
+        if (requiredInt64Group == null) {
+            throw new ApiException("Missing the required parameter 'requiredInt64Group' when calling testGroupParameters(Async)");
+        }
         
 
-        com.squareup.okhttp.Call call = testGroupParametersCall(stringGroup, booleanGroup, int64Group, progressListener, progressRequestListener);
+        com.squareup.okhttp.Call call = testGroupParametersCall(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group, progressListener, progressRequestListener);
         return call;
 
     }
@@ -1379,32 +1409,41 @@ public class FakeApi {
     /**
      * Fake endpoint to test group parameters (optional)
      * Fake endpoint to test group parameters (optional)
+     * @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 ApiException If fail to call the API, e.g. server error or cannot deserialize the response body
      */
-    public void testGroupParameters(Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
-        testGroupParametersWithHttpInfo(stringGroup, booleanGroup, int64Group);
+    public void testGroupParameters(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
+        testGroupParametersWithHttpInfo(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
     }
 
     /**
      * Fake endpoint to test group parameters (optional)
      * Fake endpoint to test group parameters (optional)
+     * @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 ApiResponse&lt;Void&gt;
      * @throws ApiException If fail to call the API, e.g. server error or cannot deserialize the response body
      */
-    public ApiResponse<Void> testGroupParametersWithHttpInfo(Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
-        com.squareup.okhttp.Call call = testGroupParametersValidateBeforeCall(stringGroup, booleanGroup, int64Group, null, null);
+    public ApiResponse<Void> testGroupParametersWithHttpInfo(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
+        com.squareup.okhttp.Call call = testGroupParametersValidateBeforeCall(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group, null, null);
         return apiClient.execute(call);
     }
 
     /**
      * Fake endpoint to test group parameters (optional) (asynchronously)
      * Fake endpoint to test group parameters (optional)
+     * @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)
@@ -1412,7 +1451,7 @@ public class FakeApi {
      * @return The request call
      * @throws ApiException If fail to process the API call, e.g. serializing the request body object
      */
-    public com.squareup.okhttp.Call testGroupParametersAsync(Integer stringGroup, Boolean booleanGroup, Long int64Group, final ApiCallback<Void> callback) throws ApiException {
+    public com.squareup.okhttp.Call testGroupParametersAsync(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group, final ApiCallback<Void> callback) throws ApiException {
 
         ProgressResponseBody.ProgressListener progressListener = null;
         ProgressRequestBody.ProgressRequestListener progressRequestListener = null;
@@ -1433,7 +1472,7 @@ public class FakeApi {
             };
         }
 
-        com.squareup.okhttp.Call call = testGroupParametersValidateBeforeCall(stringGroup, booleanGroup, int64Group, progressListener, progressRequestListener);
+        com.squareup.okhttp.Call call = testGroupParametersValidateBeforeCall(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group, progressListener, progressRequestListener);
         apiClient.executeAsync(call, callback);
         return call;
     }
diff --git a/samples/client/petstore/java/okhttp-gson-parcelableModel/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/okhttp-gson-parcelableModel/src/test/java/org/openapitools/client/api/FakeApiTest.java
index f23eef8b585..07f4a80a5b2 100644
--- a/samples/client/petstore/java/okhttp-gson-parcelableModel/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/okhttp-gson-parcelableModel/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -17,6 +17,7 @@ import org.openapitools.client.ApiException;
 import java.math.BigDecimal;
 import org.openapitools.client.model.Client;
 import java.io.File;
+import org.openapitools.client.model.FileSchemaTestClass;
 import org.threeten.bp.LocalDate;
 import org.threeten.bp.OffsetDateTime;
 import org.openapitools.client.model.OuterComposite;
@@ -102,6 +103,22 @@ public class FakeApiTest {
         // TODO: test validations
     }
     
+    /**
+     * 
+     *
+     * For this test, the body for this request much reference a schema named &#x60;File&#x60;.
+     *
+     * @throws ApiException
+     *          if the Api call fails
+     */
+    @Test
+    public void testBodyWithFileSchemaTest() throws ApiException {
+        FileSchemaTestClass fileSchemaTestClass = null;
+        api.testBodyWithFileSchema(fileSchemaTestClass);
+
+        // TODO: test validations
+    }
+    
     /**
      * 
      *
@@ -187,6 +204,27 @@ public class FakeApiTest {
         // TODO: test validations
     }
     
+    /**
+     * Fake endpoint to test group parameters (optional)
+     *
+     * Fake endpoint to test group parameters (optional)
+     *
+     * @throws ApiException
+     *          if the Api call fails
+     */
+    @Test
+    public void testGroupParametersTest() throws ApiException {
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
+        Integer stringGroup = null;
+        Boolean booleanGroup = null;
+        Long int64Group = null;
+        api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
+
+        // TODO: test validations
+    }
+    
     /**
      * test inline additionalProperties
      *
diff --git a/samples/client/petstore/java/okhttp-gson/docs/FakeApi.md b/samples/client/petstore/java/okhttp-gson/docs/FakeApi.md
index a29ac9987a3..62046473c1f 100644
--- a/samples/client/petstore/java/okhttp-gson/docs/FakeApi.md
+++ b/samples/client/petstore/java/okhttp-gson/docs/FakeApi.md
@@ -470,7 +470,7 @@ No authorization required
 
 <a name="testGroupParameters"></a>
 # **testGroupParameters**
-> testGroupParameters(stringGroup, booleanGroup, int64Group)
+> testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group)
 
 Fake endpoint to test group parameters (optional)
 
@@ -484,11 +484,14 @@ Fake endpoint to test group parameters (optional)
 
 
 FakeApi apiInstance = new FakeApi();
+Integer requiredStringGroup = 56; // Integer | Required String in group parameters
+Boolean requiredBooleanGroup = true; // Boolean | Required Boolean in group parameters
+Long requiredInt64Group = 56L; // Long | Required Integer in group parameters
 Integer stringGroup = 56; // Integer | String in group parameters
 Boolean booleanGroup = true; // Boolean | Boolean in group parameters
 Long int64Group = 56L; // Long | Integer in group parameters
 try {
-    apiInstance.testGroupParameters(stringGroup, booleanGroup, int64Group);
+    apiInstance.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 } catch (ApiException e) {
     System.err.println("Exception when calling FakeApi#testGroupParameters");
     e.printStackTrace();
@@ -499,6 +502,9 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **requiredStringGroup** | **Integer**| Required String in group parameters |
+ **requiredBooleanGroup** | **Boolean**| Required Boolean in group parameters |
+ **requiredInt64Group** | **Long**| Required Integer in group parameters |
  **stringGroup** | **Integer**| String in group parameters | [optional]
  **booleanGroup** | **Boolean**| Boolean in group parameters | [optional]
  **int64Group** | **Long**| Integer in group parameters | [optional]
diff --git a/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/api/FakeApi.java
index 783dfb78ec2..49f8a954e98 100644
--- a/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -1307,6 +1307,9 @@ public class FakeApi {
     }
     /**
      * Build call for testGroupParameters
+     * @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)
@@ -1315,7 +1318,7 @@ public class FakeApi {
      * @return Call to execute
      * @throws ApiException If fail to serialize the request body object
      */
-    public com.squareup.okhttp.Call testGroupParametersCall(Integer stringGroup, Boolean booleanGroup, Long int64Group, final ProgressResponseBody.ProgressListener progressListener, final ProgressRequestBody.ProgressRequestListener progressRequestListener) throws ApiException {
+    public com.squareup.okhttp.Call testGroupParametersCall(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group, final ProgressResponseBody.ProgressListener progressListener, final ProgressRequestBody.ProgressRequestListener progressRequestListener) throws ApiException {
         Object localVarPostBody = new Object();
 
         // create path and map variables
@@ -1323,6 +1326,14 @@ public class FakeApi {
 
         List<Pair> localVarQueryParams = new ArrayList<Pair>();
         List<Pair> localVarCollectionQueryParams = new ArrayList<Pair>();
+        if (requiredStringGroup != null) {
+            localVarQueryParams.addAll(apiClient.parameterToPair("required_string_group", requiredStringGroup));
+        }
+
+        if (requiredInt64Group != null) {
+            localVarQueryParams.addAll(apiClient.parameterToPair("required_int64_group", requiredInt64Group));
+        }
+
         if (stringGroup != null) {
             localVarQueryParams.addAll(apiClient.parameterToPair("string_group", stringGroup));
         }
@@ -1332,6 +1343,10 @@ public class FakeApi {
         }
 
         Map<String, String> localVarHeaderParams = new HashMap<String, String>();
+        if (requiredBooleanGroup != null) {
+            localVarHeaderParams.put("required_boolean_group", apiClient.parameterToString(requiredBooleanGroup));
+        }
+
         if (booleanGroup != null) {
             localVarHeaderParams.put("boolean_group", apiClient.parameterToString(booleanGroup));
         }
@@ -1368,10 +1383,25 @@ public class FakeApi {
     }
 
     @SuppressWarnings("rawtypes")
-    private com.squareup.okhttp.Call testGroupParametersValidateBeforeCall(Integer stringGroup, Boolean booleanGroup, Long int64Group, final ProgressResponseBody.ProgressListener progressListener, final ProgressRequestBody.ProgressRequestListener progressRequestListener) throws ApiException {
+    private com.squareup.okhttp.Call testGroupParametersValidateBeforeCall(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group, final ProgressResponseBody.ProgressListener progressListener, final ProgressRequestBody.ProgressRequestListener progressRequestListener) throws ApiException {
+        
+        // verify the required parameter 'requiredStringGroup' is set
+        if (requiredStringGroup == null) {
+            throw new ApiException("Missing the required parameter 'requiredStringGroup' when calling testGroupParameters(Async)");
+        }
+        
+        // verify the required parameter 'requiredBooleanGroup' is set
+        if (requiredBooleanGroup == null) {
+            throw new ApiException("Missing the required parameter 'requiredBooleanGroup' when calling testGroupParameters(Async)");
+        }
+        
+        // verify the required parameter 'requiredInt64Group' is set
+        if (requiredInt64Group == null) {
+            throw new ApiException("Missing the required parameter 'requiredInt64Group' when calling testGroupParameters(Async)");
+        }
         
 
-        com.squareup.okhttp.Call call = testGroupParametersCall(stringGroup, booleanGroup, int64Group, progressListener, progressRequestListener);
+        com.squareup.okhttp.Call call = testGroupParametersCall(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group, progressListener, progressRequestListener);
         return call;
 
     }
@@ -1379,32 +1409,41 @@ public class FakeApi {
     /**
      * Fake endpoint to test group parameters (optional)
      * Fake endpoint to test group parameters (optional)
+     * @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 ApiException If fail to call the API, e.g. server error or cannot deserialize the response body
      */
-    public void testGroupParameters(Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
-        testGroupParametersWithHttpInfo(stringGroup, booleanGroup, int64Group);
+    public void testGroupParameters(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
+        testGroupParametersWithHttpInfo(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
     }
 
     /**
      * Fake endpoint to test group parameters (optional)
      * Fake endpoint to test group parameters (optional)
+     * @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 ApiResponse&lt;Void&gt;
      * @throws ApiException If fail to call the API, e.g. server error or cannot deserialize the response body
      */
-    public ApiResponse<Void> testGroupParametersWithHttpInfo(Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
-        com.squareup.okhttp.Call call = testGroupParametersValidateBeforeCall(stringGroup, booleanGroup, int64Group, null, null);
+    public ApiResponse<Void> testGroupParametersWithHttpInfo(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
+        com.squareup.okhttp.Call call = testGroupParametersValidateBeforeCall(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group, null, null);
         return apiClient.execute(call);
     }
 
     /**
      * Fake endpoint to test group parameters (optional) (asynchronously)
      * Fake endpoint to test group parameters (optional)
+     * @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)
@@ -1412,7 +1451,7 @@ public class FakeApi {
      * @return The request call
      * @throws ApiException If fail to process the API call, e.g. serializing the request body object
      */
-    public com.squareup.okhttp.Call testGroupParametersAsync(Integer stringGroup, Boolean booleanGroup, Long int64Group, final ApiCallback<Void> callback) throws ApiException {
+    public com.squareup.okhttp.Call testGroupParametersAsync(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group, final ApiCallback<Void> callback) throws ApiException {
 
         ProgressResponseBody.ProgressListener progressListener = null;
         ProgressRequestBody.ProgressRequestListener progressRequestListener = null;
@@ -1433,7 +1472,7 @@ public class FakeApi {
             };
         }
 
-        com.squareup.okhttp.Call call = testGroupParametersValidateBeforeCall(stringGroup, booleanGroup, int64Group, progressListener, progressRequestListener);
+        com.squareup.okhttp.Call call = testGroupParametersValidateBeforeCall(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group, progressListener, progressRequestListener);
         apiClient.executeAsync(call, callback);
         return call;
     }
diff --git a/samples/client/petstore/java/okhttp-gson/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/okhttp-gson/src/test/java/org/openapitools/client/api/FakeApiTest.java
index 6fffb218baa..07f4a80a5b2 100644
--- a/samples/client/petstore/java/okhttp-gson/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/okhttp-gson/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -214,10 +214,13 @@ public class FakeApiTest {
      */
     @Test
     public void testGroupParametersTest() throws ApiException {
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
         Integer stringGroup = null;
         Boolean booleanGroup = null;
         Long int64Group = null;
-        api.testGroupParameters(stringGroup, booleanGroup, int64Group);
+        api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 
         // TODO: test validations
     }
diff --git a/samples/client/petstore/java/rest-assured/docs/FakeApi.md b/samples/client/petstore/java/rest-assured/docs/FakeApi.md
index 8d5f569c6c7..153e5030c27 100644
--- a/samples/client/petstore/java/rest-assured/docs/FakeApi.md
+++ b/samples/client/petstore/java/rest-assured/docs/FakeApi.md
@@ -416,7 +416,7 @@ No authorization required
 
 <a name="testGroupParameters"></a>
 # **testGroupParameters**
-> testGroupParameters(stringGroup, booleanGroup, int64Group)
+> testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group)
 
 Fake endpoint to test group parameters (optional)
 
@@ -433,13 +433,19 @@ FakeApi api = ApiClient.api(ApiClient.Config.apiConfig().withReqSpecSupplier(
                 () -> new RequestSpecBuilder()
                         .setBaseUri("http://petstore.swagger.io:80/v2"))).fake();
 
-api.testGroupParameters().execute(r -> r.prettyPeek());
+api.testGroupParameters()
+    .requiredStringGroupQuery(requiredStringGroup)
+    .requiredBooleanGroupHeader(requiredBooleanGroup)
+    .requiredInt64GroupQuery(requiredInt64Group).execute(r -> r.prettyPeek());
 ```
 
 ### Parameters
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **requiredStringGroup** | **Integer**| Required String in group parameters |
+ **requiredBooleanGroup** | **Boolean**| Required Boolean in group parameters |
+ **requiredInt64Group** | **Long**| Required Integer in group parameters |
  **stringGroup** | **Integer**| String in group parameters | [optional]
  **booleanGroup** | **Boolean**| Boolean in group parameters | [optional]
  **int64Group** | **Long**| Integer in group parameters | [optional]
diff --git a/samples/client/petstore/java/rest-assured/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/rest-assured/src/main/java/org/openapitools/client/api/FakeApi.java
index 991442d3dd0..ac8e81a6c37 100644
--- a/samples/client/petstore/java/rest-assured/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/rest-assured/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -1044,6 +1044,9 @@ public class FakeApi {
      * Fake endpoint to test group parameters (optional)
      * Fake endpoint to test group parameters (optional)
      *
+     * @see #requiredStringGroupQuery Required String in group parameters (required)
+     * @see #requiredBooleanGroupHeader Required Boolean in group parameters (required)
+     * @see #requiredInt64GroupQuery Required Integer in group parameters (required)
      * @see #stringGroupQuery String in group parameters (optional)
      * @see #booleanGroupHeader Boolean in group parameters (optional)
      * @see #int64GroupQuery Integer in group parameters (optional)
@@ -1072,6 +1075,17 @@ public class FakeApi {
             return handler.apply(RestAssured.given().spec(reqSpec.build()).expect().spec(respSpec.build()).when().request(REQ_METHOD, REQ_URI));
         }
 
+        public static final String REQUIRED_BOOLEAN_GROUP_HEADER = "required_boolean_group";
+
+        /**
+         * @param requiredBooleanGroup (Boolean) Required Boolean in group parameters (required)
+         * @return operation
+         */
+        public TestGroupParametersOper requiredBooleanGroupHeader(String requiredBooleanGroup) {
+            reqSpec.addHeader(REQUIRED_BOOLEAN_GROUP_HEADER, requiredBooleanGroup);
+            return this;
+        }
+
         public static final String BOOLEAN_GROUP_HEADER = "boolean_group";
 
         /**
@@ -1083,6 +1097,28 @@ public class FakeApi {
             return this;
         }
 
+        public static final String REQUIRED_STRING_GROUP_QUERY = "required_string_group";
+
+        /**
+         * @param requiredStringGroup (Integer) Required String in group parameters (required)
+         * @return operation
+         */
+        public TestGroupParametersOper requiredStringGroupQuery(Object... requiredStringGroup) {
+            reqSpec.addQueryParam(REQUIRED_STRING_GROUP_QUERY, requiredStringGroup);
+            return this;
+        }
+
+        public static final String REQUIRED_INT64_GROUP_QUERY = "required_int64_group";
+
+        /**
+         * @param requiredInt64Group (Long) Required Integer in group parameters (required)
+         * @return operation
+         */
+        public TestGroupParametersOper requiredInt64GroupQuery(Object... requiredInt64Group) {
+            reqSpec.addQueryParam(REQUIRED_INT64_GROUP_QUERY, requiredInt64Group);
+            return this;
+        }
+
         public static final String STRING_GROUP_QUERY = "string_group";
 
         /**
diff --git a/samples/client/petstore/java/rest-assured/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/rest-assured/src/test/java/org/openapitools/client/api/FakeApiTest.java
index d05c8622726..f8746ac3c95 100644
--- a/samples/client/petstore/java/rest-assured/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/rest-assured/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -230,10 +230,16 @@ public class FakeApiTest {
      */
     @Test
     public void shouldSee400AfterTestGroupParameters() {
+        Integer requiredStringGroup = null;
+        String requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
         Integer stringGroup = null;
         String booleanGroup = null;
         Long int64Group = null;
-        api.testGroupParameters().execute(r -> r.prettyPeek());
+        api.testGroupParameters()
+                .requiredStringGroupQuery(requiredStringGroup)
+                .requiredBooleanGroupHeader(requiredBooleanGroup)
+                .requiredInt64GroupQuery(requiredInt64Group).execute(r -> r.prettyPeek());
         // TODO: test validations
     }
 
diff --git a/samples/client/petstore/java/resteasy/docs/FakeApi.md b/samples/client/petstore/java/resteasy/docs/FakeApi.md
index a29ac9987a3..62046473c1f 100644
--- a/samples/client/petstore/java/resteasy/docs/FakeApi.md
+++ b/samples/client/petstore/java/resteasy/docs/FakeApi.md
@@ -470,7 +470,7 @@ No authorization required
 
 <a name="testGroupParameters"></a>
 # **testGroupParameters**
-> testGroupParameters(stringGroup, booleanGroup, int64Group)
+> testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group)
 
 Fake endpoint to test group parameters (optional)
 
@@ -484,11 +484,14 @@ Fake endpoint to test group parameters (optional)
 
 
 FakeApi apiInstance = new FakeApi();
+Integer requiredStringGroup = 56; // Integer | Required String in group parameters
+Boolean requiredBooleanGroup = true; // Boolean | Required Boolean in group parameters
+Long requiredInt64Group = 56L; // Long | Required Integer in group parameters
 Integer stringGroup = 56; // Integer | String in group parameters
 Boolean booleanGroup = true; // Boolean | Boolean in group parameters
 Long int64Group = 56L; // Long | Integer in group parameters
 try {
-    apiInstance.testGroupParameters(stringGroup, booleanGroup, int64Group);
+    apiInstance.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 } catch (ApiException e) {
     System.err.println("Exception when calling FakeApi#testGroupParameters");
     e.printStackTrace();
@@ -499,6 +502,9 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **requiredStringGroup** | **Integer**| Required String in group parameters |
+ **requiredBooleanGroup** | **Boolean**| Required Boolean in group parameters |
+ **requiredInt64Group** | **Long**| Required Integer in group parameters |
  **stringGroup** | **Integer**| String in group parameters | [optional]
  **booleanGroup** | **Boolean**| Boolean in group parameters | [optional]
  **int64Group** | **Long**| Integer in group parameters | [optional]
diff --git a/samples/client/petstore/java/resteasy/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/resteasy/src/main/java/org/openapitools/client/api/FakeApi.java
index a1c5fef69c1..dff8c8271e8 100644
--- a/samples/client/petstore/java/resteasy/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/resteasy/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -466,14 +466,32 @@ if (enumFormString != null)
   /**
    * Fake endpoint to test group parameters (optional)
    * Fake endpoint to test group parameters (optional)
+   * @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 ApiException if fails to make API call
    */
-  public void testGroupParameters(Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
+  public void testGroupParameters(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
     Object localVarPostBody = new Object();
     
+    // verify the required parameter 'requiredStringGroup' is set
+    if (requiredStringGroup == null) {
+      throw new ApiException(400, "Missing the required parameter 'requiredStringGroup' when calling testGroupParameters");
+    }
+    
+    // verify the required parameter 'requiredBooleanGroup' is set
+    if (requiredBooleanGroup == null) {
+      throw new ApiException(400, "Missing the required parameter 'requiredBooleanGroup' when calling testGroupParameters");
+    }
+    
+    // verify the required parameter 'requiredInt64Group' is set
+    if (requiredInt64Group == null) {
+      throw new ApiException(400, "Missing the required parameter 'requiredInt64Group' when calling testGroupParameters");
+    }
+    
     // create path and map variables
     String localVarPath = "/fake".replaceAll("\\{format\\}","json");
 
@@ -482,10 +500,14 @@ if (enumFormString != null)
     Map<String, String> localVarHeaderParams = new HashMap<String, String>();
     Map<String, Object> localVarFormParams = new HashMap<String, Object>();
 
+    localVarQueryParams.addAll(apiClient.parameterToPairs("", "required_string_group", requiredStringGroup));
+    localVarQueryParams.addAll(apiClient.parameterToPairs("", "required_int64_group", requiredInt64Group));
     localVarQueryParams.addAll(apiClient.parameterToPairs("", "string_group", stringGroup));
     localVarQueryParams.addAll(apiClient.parameterToPairs("", "int64_group", int64Group));
 
-    if (booleanGroup != null)
+    if (requiredBooleanGroup != null)
+      localVarHeaderParams.put("required_boolean_group", apiClient.parameterToString(requiredBooleanGroup));
+if (booleanGroup != null)
       localVarHeaderParams.put("boolean_group", apiClient.parameterToString(booleanGroup));
 
     
diff --git a/samples/client/petstore/java/resteasy/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/resteasy/src/test/java/org/openapitools/client/api/FakeApiTest.java
index f23eef8b585..07f4a80a5b2 100644
--- a/samples/client/petstore/java/resteasy/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/resteasy/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -17,6 +17,7 @@ import org.openapitools.client.ApiException;
 import java.math.BigDecimal;
 import org.openapitools.client.model.Client;
 import java.io.File;
+import org.openapitools.client.model.FileSchemaTestClass;
 import org.threeten.bp.LocalDate;
 import org.threeten.bp.OffsetDateTime;
 import org.openapitools.client.model.OuterComposite;
@@ -102,6 +103,22 @@ public class FakeApiTest {
         // TODO: test validations
     }
     
+    /**
+     * 
+     *
+     * For this test, the body for this request much reference a schema named &#x60;File&#x60;.
+     *
+     * @throws ApiException
+     *          if the Api call fails
+     */
+    @Test
+    public void testBodyWithFileSchemaTest() throws ApiException {
+        FileSchemaTestClass fileSchemaTestClass = null;
+        api.testBodyWithFileSchema(fileSchemaTestClass);
+
+        // TODO: test validations
+    }
+    
     /**
      * 
      *
@@ -187,6 +204,27 @@ public class FakeApiTest {
         // TODO: test validations
     }
     
+    /**
+     * Fake endpoint to test group parameters (optional)
+     *
+     * Fake endpoint to test group parameters (optional)
+     *
+     * @throws ApiException
+     *          if the Api call fails
+     */
+    @Test
+    public void testGroupParametersTest() throws ApiException {
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
+        Integer stringGroup = null;
+        Boolean booleanGroup = null;
+        Long int64Group = null;
+        api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
+
+        // TODO: test validations
+    }
+    
     /**
      * test inline additionalProperties
      *
diff --git a/samples/client/petstore/java/resttemplate-withXml/docs/FakeApi.md b/samples/client/petstore/java/resttemplate-withXml/docs/FakeApi.md
index a29ac9987a3..62046473c1f 100644
--- a/samples/client/petstore/java/resttemplate-withXml/docs/FakeApi.md
+++ b/samples/client/petstore/java/resttemplate-withXml/docs/FakeApi.md
@@ -470,7 +470,7 @@ No authorization required
 
 <a name="testGroupParameters"></a>
 # **testGroupParameters**
-> testGroupParameters(stringGroup, booleanGroup, int64Group)
+> testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group)
 
 Fake endpoint to test group parameters (optional)
 
@@ -484,11 +484,14 @@ Fake endpoint to test group parameters (optional)
 
 
 FakeApi apiInstance = new FakeApi();
+Integer requiredStringGroup = 56; // Integer | Required String in group parameters
+Boolean requiredBooleanGroup = true; // Boolean | Required Boolean in group parameters
+Long requiredInt64Group = 56L; // Long | Required Integer in group parameters
 Integer stringGroup = 56; // Integer | String in group parameters
 Boolean booleanGroup = true; // Boolean | Boolean in group parameters
 Long int64Group = 56L; // Long | Integer in group parameters
 try {
-    apiInstance.testGroupParameters(stringGroup, booleanGroup, int64Group);
+    apiInstance.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 } catch (ApiException e) {
     System.err.println("Exception when calling FakeApi#testGroupParameters");
     e.printStackTrace();
@@ -499,6 +502,9 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **requiredStringGroup** | **Integer**| Required String in group parameters |
+ **requiredBooleanGroup** | **Boolean**| Required Boolean in group parameters |
+ **requiredInt64Group** | **Long**| Required Integer in group parameters |
  **stringGroup** | **Integer**| String in group parameters | [optional]
  **booleanGroup** | **Boolean**| Boolean in group parameters | [optional]
  **int64Group** | **Long**| Integer in group parameters | [optional]
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 4a3cd69107c..725ad066104 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
@@ -425,23 +425,45 @@ public class FakeApi {
      * 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
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
-    public void testGroupParameters(Integer stringGroup, Boolean booleanGroup, Long int64Group) throws RestClientException {
+    public void testGroupParameters(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws RestClientException {
         Object postBody = null;
         
+        // verify the required parameter 'requiredStringGroup' is set
+        if (requiredStringGroup == null) {
+            throw new HttpClientErrorException(HttpStatus.BAD_REQUEST, "Missing the required parameter 'requiredStringGroup' when calling testGroupParameters");
+        }
+        
+        // verify the required parameter 'requiredBooleanGroup' is set
+        if (requiredBooleanGroup == null) {
+            throw new HttpClientErrorException(HttpStatus.BAD_REQUEST, "Missing the required parameter 'requiredBooleanGroup' when calling testGroupParameters");
+        }
+        
+        // verify the required parameter 'requiredInt64Group' is set
+        if (requiredInt64Group == null) {
+            throw new HttpClientErrorException(HttpStatus.BAD_REQUEST, "Missing the required parameter 'requiredInt64Group' when calling testGroupParameters");
+        }
+        
         String path = UriComponentsBuilder.fromPath("/fake").build().toUriString();
         
         final MultiValueMap<String, String> queryParams = new LinkedMultiValueMap<String, String>();
         final HttpHeaders headerParams = new HttpHeaders();
         final MultiValueMap<String, Object> formParams = new LinkedMultiValueMap<String, Object>();
         
+        queryParams.putAll(apiClient.parameterToMultiValueMap(null, "required_string_group", requiredStringGroup));
+        queryParams.putAll(apiClient.parameterToMultiValueMap(null, "required_int64_group", requiredInt64Group));
         queryParams.putAll(apiClient.parameterToMultiValueMap(null, "string_group", stringGroup));
         queryParams.putAll(apiClient.parameterToMultiValueMap(null, "int64_group", int64Group));
         
+        if (requiredBooleanGroup != null)
+        headerParams.add("required_boolean_group", apiClient.parameterToString(requiredBooleanGroup));
         if (booleanGroup != null)
         headerParams.add("boolean_group", apiClient.parameterToString(booleanGroup));
 
diff --git a/samples/client/petstore/java/resttemplate-withXml/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/resttemplate-withXml/src/test/java/org/openapitools/client/api/FakeApiTest.java
index 373a0c691c7..5d14435fc03 100644
--- a/samples/client/petstore/java/resttemplate-withXml/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/resttemplate-withXml/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -16,6 +16,7 @@ package org.openapitools.client.api;
 import java.math.BigDecimal;
 import org.openapitools.client.model.Client;
 import java.io.File;
+import org.openapitools.client.model.FileSchemaTestClass;
 import org.threeten.bp.LocalDate;
 import org.threeten.bp.OffsetDateTime;
 import org.openapitools.client.model.OuterComposite;
@@ -101,6 +102,22 @@ public class FakeApiTest {
         // TODO: test validations
     }
     
+    /**
+     * 
+     *
+     * For this test, the body for this request much reference a schema named &#x60;File&#x60;.
+     *
+     * @throws ApiException
+     *          if the Api call fails
+     */
+    @Test
+    public void testBodyWithFileSchemaTest() {
+        FileSchemaTestClass fileSchemaTestClass = null;
+        api.testBodyWithFileSchema(fileSchemaTestClass);
+
+        // TODO: test validations
+    }
+    
     /**
      * 
      *
@@ -186,6 +203,27 @@ public class FakeApiTest {
         // TODO: test validations
     }
     
+    /**
+     * Fake endpoint to test group parameters (optional)
+     *
+     * Fake endpoint to test group parameters (optional)
+     *
+     * @throws ApiException
+     *          if the Api call fails
+     */
+    @Test
+    public void testGroupParametersTest() {
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
+        Integer stringGroup = null;
+        Boolean booleanGroup = null;
+        Long int64Group = null;
+        api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
+
+        // TODO: test validations
+    }
+    
     /**
      * test inline additionalProperties
      *
diff --git a/samples/client/petstore/java/resttemplate/docs/FakeApi.md b/samples/client/petstore/java/resttemplate/docs/FakeApi.md
index a29ac9987a3..62046473c1f 100644
--- a/samples/client/petstore/java/resttemplate/docs/FakeApi.md
+++ b/samples/client/petstore/java/resttemplate/docs/FakeApi.md
@@ -470,7 +470,7 @@ No authorization required
 
 <a name="testGroupParameters"></a>
 # **testGroupParameters**
-> testGroupParameters(stringGroup, booleanGroup, int64Group)
+> testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group)
 
 Fake endpoint to test group parameters (optional)
 
@@ -484,11 +484,14 @@ Fake endpoint to test group parameters (optional)
 
 
 FakeApi apiInstance = new FakeApi();
+Integer requiredStringGroup = 56; // Integer | Required String in group parameters
+Boolean requiredBooleanGroup = true; // Boolean | Required Boolean in group parameters
+Long requiredInt64Group = 56L; // Long | Required Integer in group parameters
 Integer stringGroup = 56; // Integer | String in group parameters
 Boolean booleanGroup = true; // Boolean | Boolean in group parameters
 Long int64Group = 56L; // Long | Integer in group parameters
 try {
-    apiInstance.testGroupParameters(stringGroup, booleanGroup, int64Group);
+    apiInstance.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 } catch (ApiException e) {
     System.err.println("Exception when calling FakeApi#testGroupParameters");
     e.printStackTrace();
@@ -499,6 +502,9 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **requiredStringGroup** | **Integer**| Required String in group parameters |
+ **requiredBooleanGroup** | **Boolean**| Required Boolean in group parameters |
+ **requiredInt64Group** | **Long**| Required Integer in group parameters |
  **stringGroup** | **Integer**| String in group parameters | [optional]
  **booleanGroup** | **Boolean**| Boolean in group parameters | [optional]
  **int64Group** | **Long**| Integer in group parameters | [optional]
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 4a3cd69107c..725ad066104 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
@@ -425,23 +425,45 @@ public class FakeApi {
      * 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
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
-    public void testGroupParameters(Integer stringGroup, Boolean booleanGroup, Long int64Group) throws RestClientException {
+    public void testGroupParameters(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws RestClientException {
         Object postBody = null;
         
+        // verify the required parameter 'requiredStringGroup' is set
+        if (requiredStringGroup == null) {
+            throw new HttpClientErrorException(HttpStatus.BAD_REQUEST, "Missing the required parameter 'requiredStringGroup' when calling testGroupParameters");
+        }
+        
+        // verify the required parameter 'requiredBooleanGroup' is set
+        if (requiredBooleanGroup == null) {
+            throw new HttpClientErrorException(HttpStatus.BAD_REQUEST, "Missing the required parameter 'requiredBooleanGroup' when calling testGroupParameters");
+        }
+        
+        // verify the required parameter 'requiredInt64Group' is set
+        if (requiredInt64Group == null) {
+            throw new HttpClientErrorException(HttpStatus.BAD_REQUEST, "Missing the required parameter 'requiredInt64Group' when calling testGroupParameters");
+        }
+        
         String path = UriComponentsBuilder.fromPath("/fake").build().toUriString();
         
         final MultiValueMap<String, String> queryParams = new LinkedMultiValueMap<String, String>();
         final HttpHeaders headerParams = new HttpHeaders();
         final MultiValueMap<String, Object> formParams = new LinkedMultiValueMap<String, Object>();
         
+        queryParams.putAll(apiClient.parameterToMultiValueMap(null, "required_string_group", requiredStringGroup));
+        queryParams.putAll(apiClient.parameterToMultiValueMap(null, "required_int64_group", requiredInt64Group));
         queryParams.putAll(apiClient.parameterToMultiValueMap(null, "string_group", stringGroup));
         queryParams.putAll(apiClient.parameterToMultiValueMap(null, "int64_group", int64Group));
         
+        if (requiredBooleanGroup != null)
+        headerParams.add("required_boolean_group", apiClient.parameterToString(requiredBooleanGroup));
         if (booleanGroup != null)
         headerParams.add("boolean_group", apiClient.parameterToString(booleanGroup));
 
diff --git a/samples/client/petstore/java/resttemplate/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/resttemplate/src/test/java/org/openapitools/client/api/FakeApiTest.java
index 373a0c691c7..5d14435fc03 100644
--- a/samples/client/petstore/java/resttemplate/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/resttemplate/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -16,6 +16,7 @@ package org.openapitools.client.api;
 import java.math.BigDecimal;
 import org.openapitools.client.model.Client;
 import java.io.File;
+import org.openapitools.client.model.FileSchemaTestClass;
 import org.threeten.bp.LocalDate;
 import org.threeten.bp.OffsetDateTime;
 import org.openapitools.client.model.OuterComposite;
@@ -101,6 +102,22 @@ public class FakeApiTest {
         // TODO: test validations
     }
     
+    /**
+     * 
+     *
+     * For this test, the body for this request much reference a schema named &#x60;File&#x60;.
+     *
+     * @throws ApiException
+     *          if the Api call fails
+     */
+    @Test
+    public void testBodyWithFileSchemaTest() {
+        FileSchemaTestClass fileSchemaTestClass = null;
+        api.testBodyWithFileSchema(fileSchemaTestClass);
+
+        // TODO: test validations
+    }
+    
     /**
      * 
      *
@@ -186,6 +203,27 @@ public class FakeApiTest {
         // TODO: test validations
     }
     
+    /**
+     * Fake endpoint to test group parameters (optional)
+     *
+     * Fake endpoint to test group parameters (optional)
+     *
+     * @throws ApiException
+     *          if the Api call fails
+     */
+    @Test
+    public void testGroupParametersTest() {
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
+        Integer stringGroup = null;
+        Boolean booleanGroup = null;
+        Long int64Group = null;
+        api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
+
+        // TODO: test validations
+    }
+    
     /**
      * test inline additionalProperties
      *
diff --git a/samples/client/petstore/java/retrofit/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/retrofit/src/main/java/org/openapitools/client/api/FakeApi.java
index ed7fb62be50..a83105fd0d3 100644
--- a/samples/client/petstore/java/retrofit/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/retrofit/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -287,6 +287,9 @@ public interface FakeApi {
    * Fake endpoint to test group parameters (optional)
    * Sync method
    * Fake endpoint to test group parameters (optional)
+   * @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)
@@ -295,12 +298,15 @@ public interface FakeApi {
   
   @DELETE("/fake")
   Void testGroupParameters(
-    @retrofit.http.Query("string_group") Integer stringGroup, @retrofit.http.Header("boolean_group") Boolean booleanGroup, @retrofit.http.Query("int64_group") Long int64Group
+    @retrofit.http.Query("required_string_group") Integer requiredStringGroup, @retrofit.http.Header("required_boolean_group") Boolean requiredBooleanGroup, @retrofit.http.Query("required_int64_group") Long requiredInt64Group, @retrofit.http.Query("string_group") Integer stringGroup, @retrofit.http.Header("boolean_group") Boolean booleanGroup, @retrofit.http.Query("int64_group") Long int64Group
   );
 
   /**
    * Fake endpoint to test group parameters (optional)
    * Async method
+   * @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)
@@ -309,7 +315,7 @@ public interface FakeApi {
   
   @DELETE("/fake")
   void testGroupParameters(
-    @retrofit.http.Query("string_group") Integer stringGroup, @retrofit.http.Header("boolean_group") Boolean booleanGroup, @retrofit.http.Query("int64_group") Long int64Group, Callback<Void> cb
+    @retrofit.http.Query("required_string_group") Integer requiredStringGroup, @retrofit.http.Header("required_boolean_group") Boolean requiredBooleanGroup, @retrofit.http.Query("required_int64_group") Long requiredInt64Group, @retrofit.http.Query("string_group") Integer stringGroup, @retrofit.http.Header("boolean_group") Boolean booleanGroup, @retrofit.http.Query("int64_group") Long int64Group, Callback<Void> cb
   );
   /**
    * test inline additionalProperties
diff --git a/samples/client/petstore/java/retrofit/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/retrofit/src/test/java/org/openapitools/client/api/FakeApiTest.java
index c5094b98fd5..d055e54ede9 100644
--- a/samples/client/petstore/java/retrofit/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/retrofit/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -5,6 +5,7 @@ import java.math.BigDecimal;
 import org.openapitools.client.model.Client;
 import org.joda.time.DateTime;
 import java.io.File;
+import org.openapitools.client.model.FileSchemaTestClass;
 import org.joda.time.LocalDate;
 import org.openapitools.client.model.OuterComposite;
 import org.openapitools.client.model.User;
@@ -81,6 +82,19 @@ public class FakeApiTest {
         // TODO: test validations
     }
     
+    /**
+     * 
+     *
+     * For this test, the body for this request much reference a schema named &#x60;File&#x60;.
+     */
+    @Test
+    public void testBodyWithFileSchemaTest() {
+        FileSchemaTestClass fileSchemaTestClass = null;
+        // api.testBodyWithFileSchema(fileSchemaTestClass);
+
+        // TODO: test validations
+    }
+    
     /**
      * 
      *
@@ -154,6 +168,24 @@ public class FakeApiTest {
         // TODO: test validations
     }
     
+    /**
+     * Fake endpoint to test group parameters (optional)
+     *
+     * Fake endpoint to test group parameters (optional)
+     */
+    @Test
+    public void testGroupParametersTest() {
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
+        Integer stringGroup = null;
+        Boolean booleanGroup = null;
+        Long int64Group = null;
+        // api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
+
+        // TODO: test validations
+    }
+    
     /**
      * test inline additionalProperties
      *
diff --git a/samples/client/petstore/java/retrofit2-play24/docs/FakeApi.md b/samples/client/petstore/java/retrofit2-play24/docs/FakeApi.md
index 3caa786e5ac..5335c1521aa 100644
--- a/samples/client/petstore/java/retrofit2-play24/docs/FakeApi.md
+++ b/samples/client/petstore/java/retrofit2-play24/docs/FakeApi.md
@@ -470,7 +470,7 @@ No authorization required
 
 <a name="testGroupParameters"></a>
 # **testGroupParameters**
-> testGroupParameters(stringGroup, booleanGroup, int64Group)
+> testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group)
 
 Fake endpoint to test group parameters (optional)
 
@@ -484,11 +484,14 @@ Fake endpoint to test group parameters (optional)
 
 
 FakeApi apiInstance = new FakeApi();
+Integer requiredStringGroup = 56; // Integer | Required String in group parameters
+Boolean requiredBooleanGroup = true; // Boolean | Required Boolean in group parameters
+Long requiredInt64Group = 56L; // Long | Required Integer in group parameters
 Integer stringGroup = 56; // Integer | String in group parameters
 Boolean booleanGroup = true; // Boolean | Boolean in group parameters
 Long int64Group = 56L; // Long | Integer in group parameters
 try {
-    apiInstance.testGroupParameters(stringGroup, booleanGroup, int64Group);
+    apiInstance.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 } catch (ApiException e) {
     System.err.println("Exception when calling FakeApi#testGroupParameters");
     e.printStackTrace();
@@ -499,6 +502,9 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **requiredStringGroup** | **Integer**| Required String in group parameters |
+ **requiredBooleanGroup** | **Boolean**| Required Boolean in group parameters |
+ **requiredInt64Group** | **Long**| Required Integer in group parameters |
  **stringGroup** | **Integer**| String in group parameters | [optional]
  **booleanGroup** | **Boolean**| Boolean in group parameters | [optional]
  **int64Group** | **Long**| Integer in group parameters | [optional]
diff --git a/samples/client/petstore/java/retrofit2-play24/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/retrofit2-play24/src/main/java/org/openapitools/client/api/FakeApi.java
index 84745f86ce9..88d49bfb020 100644
--- a/samples/client/petstore/java/retrofit2-play24/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/retrofit2-play24/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -163,6 +163,9 @@ public interface FakeApi {
   /**
    * Fake endpoint to test group parameters (optional)
    * Fake endpoint to test group parameters (optional)
+   * @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)
@@ -170,7 +173,7 @@ public interface FakeApi {
    */
   @DELETE("fake")
   F.Promise<Response<Void>> testGroupParameters(
-    @retrofit2.http.Query("string_group") Integer stringGroup, @retrofit2.http.Header("boolean_group") Boolean booleanGroup, @retrofit2.http.Query("int64_group") Long int64Group
+    @retrofit2.http.Query("required_string_group") Integer requiredStringGroup, @retrofit2.http.Header("required_boolean_group") Boolean requiredBooleanGroup, @retrofit2.http.Query("required_int64_group") Long requiredInt64Group, @retrofit2.http.Query("string_group") Integer stringGroup, @retrofit2.http.Header("boolean_group") Boolean booleanGroup, @retrofit2.http.Query("int64_group") Long int64Group
   );
 
   /**
diff --git a/samples/client/petstore/java/retrofit2-play24/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/retrofit2-play24/src/test/java/org/openapitools/client/api/FakeApiTest.java
index 649446d984c..82a96b9818b 100644
--- a/samples/client/petstore/java/retrofit2-play24/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/retrofit2-play24/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -4,6 +4,7 @@ import org.openapitools.client.ApiClient;
 import java.math.BigDecimal;
 import org.openapitools.client.model.Client;
 import java.io.File;
+import org.openapitools.client.model.FileSchemaTestClass;
 import java.time.LocalDate;
 import java.time.OffsetDateTime;
 import org.openapitools.client.model.OuterComposite;
@@ -76,6 +77,18 @@ public class FakeApiTest {
 
         // TODO: test validations
     }
+    /**
+     * 
+     *
+     * For this test, the body for this request much reference a schema named &#x60;File&#x60;.
+     */
+    @Test
+    public void testBodyWithFileSchemaTest() {
+        FileSchemaTestClass fileSchemaTestClass = null;
+        // api.testBodyWithFileSchema(fileSchemaTestClass);
+
+        // TODO: test validations
+    }
     /**
      * 
      *
@@ -145,6 +158,23 @@ public class FakeApiTest {
 
         // TODO: test validations
     }
+    /**
+     * Fake endpoint to test group parameters (optional)
+     *
+     * Fake endpoint to test group parameters (optional)
+     */
+    @Test
+    public void testGroupParametersTest() {
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
+        Integer stringGroup = null;
+        Boolean booleanGroup = null;
+        Long int64Group = null;
+        // api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
+
+        // TODO: test validations
+    }
     /**
      * test inline additionalProperties
      *
diff --git a/samples/client/petstore/java/retrofit2-play25/docs/FakeApi.md b/samples/client/petstore/java/retrofit2-play25/docs/FakeApi.md
index 3caa786e5ac..5335c1521aa 100644
--- a/samples/client/petstore/java/retrofit2-play25/docs/FakeApi.md
+++ b/samples/client/petstore/java/retrofit2-play25/docs/FakeApi.md
@@ -470,7 +470,7 @@ No authorization required
 
 <a name="testGroupParameters"></a>
 # **testGroupParameters**
-> testGroupParameters(stringGroup, booleanGroup, int64Group)
+> testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group)
 
 Fake endpoint to test group parameters (optional)
 
@@ -484,11 +484,14 @@ Fake endpoint to test group parameters (optional)
 
 
 FakeApi apiInstance = new FakeApi();
+Integer requiredStringGroup = 56; // Integer | Required String in group parameters
+Boolean requiredBooleanGroup = true; // Boolean | Required Boolean in group parameters
+Long requiredInt64Group = 56L; // Long | Required Integer in group parameters
 Integer stringGroup = 56; // Integer | String in group parameters
 Boolean booleanGroup = true; // Boolean | Boolean in group parameters
 Long int64Group = 56L; // Long | Integer in group parameters
 try {
-    apiInstance.testGroupParameters(stringGroup, booleanGroup, int64Group);
+    apiInstance.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 } catch (ApiException e) {
     System.err.println("Exception when calling FakeApi#testGroupParameters");
     e.printStackTrace();
@@ -499,6 +502,9 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **requiredStringGroup** | **Integer**| Required String in group parameters |
+ **requiredBooleanGroup** | **Boolean**| Required Boolean in group parameters |
+ **requiredInt64Group** | **Long**| Required Integer in group parameters |
  **stringGroup** | **Integer**| String in group parameters | [optional]
  **booleanGroup** | **Boolean**| Boolean in group parameters | [optional]
  **int64Group** | **Long**| Integer in group parameters | [optional]
diff --git a/samples/client/petstore/java/retrofit2-play25/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/retrofit2-play25/src/main/java/org/openapitools/client/api/FakeApi.java
index 3394d297167..c542ee4d79c 100644
--- a/samples/client/petstore/java/retrofit2-play25/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/retrofit2-play25/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -163,6 +163,9 @@ public interface FakeApi {
   /**
    * Fake endpoint to test group parameters (optional)
    * Fake endpoint to test group parameters (optional)
+   * @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)
@@ -170,7 +173,7 @@ public interface FakeApi {
    */
   @DELETE("fake")
   CompletionStage<Response<Void>> testGroupParameters(
-    @retrofit2.http.Query("string_group") Integer stringGroup, @retrofit2.http.Header("boolean_group") Boolean booleanGroup, @retrofit2.http.Query("int64_group") Long int64Group
+    @retrofit2.http.Query("required_string_group") Integer requiredStringGroup, @retrofit2.http.Header("required_boolean_group") Boolean requiredBooleanGroup, @retrofit2.http.Query("required_int64_group") Long requiredInt64Group, @retrofit2.http.Query("string_group") Integer stringGroup, @retrofit2.http.Header("boolean_group") Boolean booleanGroup, @retrofit2.http.Query("int64_group") Long int64Group
   );
 
   /**
diff --git a/samples/client/petstore/java/retrofit2-play25/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/retrofit2-play25/src/test/java/org/openapitools/client/api/FakeApiTest.java
index c7caf851a43..aec2e41c34e 100644
--- a/samples/client/petstore/java/retrofit2-play25/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/retrofit2-play25/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -4,6 +4,7 @@ import org.openapitools.client.ApiClient;
 import java.math.BigDecimal;
 import org.openapitools.client.model.Client;
 import java.io.File;
+import org.openapitools.client.model.FileSchemaTestClass;
 import org.threeten.bp.LocalDate;
 import org.threeten.bp.OffsetDateTime;
 import org.openapitools.client.model.OuterComposite;
@@ -76,6 +77,18 @@ public class FakeApiTest {
 
         // TODO: test validations
     }
+    /**
+     * 
+     *
+     * For this test, the body for this request much reference a schema named &#x60;File&#x60;.
+     */
+    @Test
+    public void testBodyWithFileSchemaTest() {
+        FileSchemaTestClass fileSchemaTestClass = null;
+        // api.testBodyWithFileSchema(fileSchemaTestClass);
+
+        // TODO: test validations
+    }
     /**
      * 
      *
@@ -145,6 +158,23 @@ public class FakeApiTest {
 
         // TODO: test validations
     }
+    /**
+     * Fake endpoint to test group parameters (optional)
+     *
+     * Fake endpoint to test group parameters (optional)
+     */
+    @Test
+    public void testGroupParametersTest() {
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
+        Integer stringGroup = null;
+        Boolean booleanGroup = null;
+        Long int64Group = null;
+        // api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
+
+        // TODO: test validations
+    }
     /**
      * test inline additionalProperties
      *
diff --git a/samples/client/petstore/java/retrofit2-play26/docs/FakeApi.md b/samples/client/petstore/java/retrofit2-play26/docs/FakeApi.md
index 3caa786e5ac..5335c1521aa 100644
--- a/samples/client/petstore/java/retrofit2-play26/docs/FakeApi.md
+++ b/samples/client/petstore/java/retrofit2-play26/docs/FakeApi.md
@@ -470,7 +470,7 @@ No authorization required
 
 <a name="testGroupParameters"></a>
 # **testGroupParameters**
-> testGroupParameters(stringGroup, booleanGroup, int64Group)
+> testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group)
 
 Fake endpoint to test group parameters (optional)
 
@@ -484,11 +484,14 @@ Fake endpoint to test group parameters (optional)
 
 
 FakeApi apiInstance = new FakeApi();
+Integer requiredStringGroup = 56; // Integer | Required String in group parameters
+Boolean requiredBooleanGroup = true; // Boolean | Required Boolean in group parameters
+Long requiredInt64Group = 56L; // Long | Required Integer in group parameters
 Integer stringGroup = 56; // Integer | String in group parameters
 Boolean booleanGroup = true; // Boolean | Boolean in group parameters
 Long int64Group = 56L; // Long | Integer in group parameters
 try {
-    apiInstance.testGroupParameters(stringGroup, booleanGroup, int64Group);
+    apiInstance.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 } catch (ApiException e) {
     System.err.println("Exception when calling FakeApi#testGroupParameters");
     e.printStackTrace();
@@ -499,6 +502,9 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **requiredStringGroup** | **Integer**| Required String in group parameters |
+ **requiredBooleanGroup** | **Boolean**| Required Boolean in group parameters |
+ **requiredInt64Group** | **Long**| Required Integer in group parameters |
  **stringGroup** | **Integer**| String in group parameters | [optional]
  **booleanGroup** | **Boolean**| Boolean in group parameters | [optional]
  **int64Group** | **Long**| Integer in group parameters | [optional]
diff --git a/samples/client/petstore/java/retrofit2-play26/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/retrofit2-play26/src/main/java/org/openapitools/client/api/FakeApi.java
index 3394d297167..c542ee4d79c 100644
--- a/samples/client/petstore/java/retrofit2-play26/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/retrofit2-play26/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -163,6 +163,9 @@ public interface FakeApi {
   /**
    * Fake endpoint to test group parameters (optional)
    * Fake endpoint to test group parameters (optional)
+   * @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)
@@ -170,7 +173,7 @@ public interface FakeApi {
    */
   @DELETE("fake")
   CompletionStage<Response<Void>> testGroupParameters(
-    @retrofit2.http.Query("string_group") Integer stringGroup, @retrofit2.http.Header("boolean_group") Boolean booleanGroup, @retrofit2.http.Query("int64_group") Long int64Group
+    @retrofit2.http.Query("required_string_group") Integer requiredStringGroup, @retrofit2.http.Header("required_boolean_group") Boolean requiredBooleanGroup, @retrofit2.http.Query("required_int64_group") Long requiredInt64Group, @retrofit2.http.Query("string_group") Integer stringGroup, @retrofit2.http.Header("boolean_group") Boolean booleanGroup, @retrofit2.http.Query("int64_group") Long int64Group
   );
 
   /**
diff --git a/samples/client/petstore/java/retrofit2-play26/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/retrofit2-play26/src/test/java/org/openapitools/client/api/FakeApiTest.java
index 4889e92772c..aec2e41c34e 100644
--- a/samples/client/petstore/java/retrofit2-play26/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/retrofit2-play26/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -1,17 +1,19 @@
 package org.openapitools.client.api;
 
-import org.junit.Before;
-import org.junit.Test;
 import org.openapitools.client.ApiClient;
+import java.math.BigDecimal;
 import org.openapitools.client.model.Client;
+import java.io.File;
 import org.openapitools.client.model.FileSchemaTestClass;
-import org.openapitools.client.model.OuterComposite;
-import org.openapitools.client.model.User;
 import org.threeten.bp.LocalDate;
 import org.threeten.bp.OffsetDateTime;
+import org.openapitools.client.model.OuterComposite;
+import org.openapitools.client.model.User;
+import org.junit.Before;
+import org.junit.Test;
 
-import java.io.File;
-import java.math.BigDecimal;
+import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
@@ -28,7 +30,7 @@ public class FakeApiTest {
     }
 
     /**
-     *
+     * 
      *
      * Test serialization of outer boolean types
      */
@@ -40,7 +42,7 @@ public class FakeApiTest {
         // TODO: test validations
     }
     /**
-     *
+     * 
      *
      * Test serialization of object with outer number type
      */
@@ -52,7 +54,7 @@ public class FakeApiTest {
         // TODO: test validations
     }
     /**
-     *
+     * 
      *
      * Test serialization of outer number types
      */
@@ -64,7 +66,7 @@ public class FakeApiTest {
         // TODO: test validations
     }
     /**
-     *
+     * 
      *
      * Test serialization of outer string types
      */
@@ -76,7 +78,7 @@ public class FakeApiTest {
         // TODO: test validations
     }
     /**
-     *
+     * 
      *
      * For this test, the body for this request much reference a schema named &#x60;File&#x60;.
      */
@@ -88,9 +90,9 @@ public class FakeApiTest {
         // TODO: test validations
     }
     /**
+     * 
      *
-     *
-     *
+     * 
      */
     @Test
     public void testBodyWithQueryParamsTest() {
@@ -113,9 +115,9 @@ public class FakeApiTest {
         // TODO: test validations
     }
     /**
-     * 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 
      *
-     * 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 
      */
     @Test
     public void testEndpointParametersTest() {
@@ -156,10 +158,27 @@ public class FakeApiTest {
 
         // TODO: test validations
     }
+    /**
+     * Fake endpoint to test group parameters (optional)
+     *
+     * Fake endpoint to test group parameters (optional)
+     */
+    @Test
+    public void testGroupParametersTest() {
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
+        Integer stringGroup = null;
+        Boolean booleanGroup = null;
+        Long int64Group = null;
+        // api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
+
+        // TODO: test validations
+    }
     /**
      * test inline additionalProperties
      *
-     *
+     * 
      */
     @Test
     public void testInlineAdditionalPropertiesTest() {
@@ -171,7 +190,7 @@ public class FakeApiTest {
     /**
      * test json serialization of form data
      *
-     *
+     * 
      */
     @Test
     public void testJsonFormDataTest() {
diff --git a/samples/client/petstore/java/retrofit2/docs/FakeApi.md b/samples/client/petstore/java/retrofit2/docs/FakeApi.md
index 3caa786e5ac..5335c1521aa 100644
--- a/samples/client/petstore/java/retrofit2/docs/FakeApi.md
+++ b/samples/client/petstore/java/retrofit2/docs/FakeApi.md
@@ -470,7 +470,7 @@ No authorization required
 
 <a name="testGroupParameters"></a>
 # **testGroupParameters**
-> testGroupParameters(stringGroup, booleanGroup, int64Group)
+> testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group)
 
 Fake endpoint to test group parameters (optional)
 
@@ -484,11 +484,14 @@ Fake endpoint to test group parameters (optional)
 
 
 FakeApi apiInstance = new FakeApi();
+Integer requiredStringGroup = 56; // Integer | Required String in group parameters
+Boolean requiredBooleanGroup = true; // Boolean | Required Boolean in group parameters
+Long requiredInt64Group = 56L; // Long | Required Integer in group parameters
 Integer stringGroup = 56; // Integer | String in group parameters
 Boolean booleanGroup = true; // Boolean | Boolean in group parameters
 Long int64Group = 56L; // Long | Integer in group parameters
 try {
-    apiInstance.testGroupParameters(stringGroup, booleanGroup, int64Group);
+    apiInstance.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 } catch (ApiException e) {
     System.err.println("Exception when calling FakeApi#testGroupParameters");
     e.printStackTrace();
@@ -499,6 +502,9 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **requiredStringGroup** | **Integer**| Required String in group parameters |
+ **requiredBooleanGroup** | **Boolean**| Required Boolean in group parameters |
+ **requiredInt64Group** | **Long**| Required Integer in group parameters |
  **stringGroup** | **Integer**| String in group parameters | [optional]
  **booleanGroup** | **Boolean**| Boolean in group parameters | [optional]
  **int64Group** | **Long**| Integer in group parameters | [optional]
diff --git a/samples/client/petstore/java/retrofit2/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/retrofit2/src/main/java/org/openapitools/client/api/FakeApi.java
index 1f6a1f76981..42da2aed960 100644
--- a/samples/client/petstore/java/retrofit2/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/retrofit2/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -158,6 +158,9 @@ public interface FakeApi {
   /**
    * Fake endpoint to test group parameters (optional)
    * Fake endpoint to test group parameters (optional)
+   * @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)
@@ -165,7 +168,7 @@ public interface FakeApi {
    */
   @DELETE("fake")
   Call<Void> testGroupParameters(
-    @retrofit2.http.Query("string_group") Integer stringGroup, @retrofit2.http.Header("boolean_group") Boolean booleanGroup, @retrofit2.http.Query("int64_group") Long int64Group
+    @retrofit2.http.Query("required_string_group") Integer requiredStringGroup, @retrofit2.http.Header("required_boolean_group") Boolean requiredBooleanGroup, @retrofit2.http.Query("required_int64_group") Long requiredInt64Group, @retrofit2.http.Query("string_group") Integer stringGroup, @retrofit2.http.Header("boolean_group") Boolean booleanGroup, @retrofit2.http.Query("int64_group") Long int64Group
   );
 
   /**
diff --git a/samples/client/petstore/java/retrofit2/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/retrofit2/src/test/java/org/openapitools/client/api/FakeApiTest.java
index c7caf851a43..aec2e41c34e 100644
--- a/samples/client/petstore/java/retrofit2/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/retrofit2/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -4,6 +4,7 @@ import org.openapitools.client.ApiClient;
 import java.math.BigDecimal;
 import org.openapitools.client.model.Client;
 import java.io.File;
+import org.openapitools.client.model.FileSchemaTestClass;
 import org.threeten.bp.LocalDate;
 import org.threeten.bp.OffsetDateTime;
 import org.openapitools.client.model.OuterComposite;
@@ -76,6 +77,18 @@ public class FakeApiTest {
 
         // TODO: test validations
     }
+    /**
+     * 
+     *
+     * For this test, the body for this request much reference a schema named &#x60;File&#x60;.
+     */
+    @Test
+    public void testBodyWithFileSchemaTest() {
+        FileSchemaTestClass fileSchemaTestClass = null;
+        // api.testBodyWithFileSchema(fileSchemaTestClass);
+
+        // TODO: test validations
+    }
     /**
      * 
      *
@@ -145,6 +158,23 @@ public class FakeApiTest {
 
         // TODO: test validations
     }
+    /**
+     * Fake endpoint to test group parameters (optional)
+     *
+     * Fake endpoint to test group parameters (optional)
+     */
+    @Test
+    public void testGroupParametersTest() {
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
+        Integer stringGroup = null;
+        Boolean booleanGroup = null;
+        Long int64Group = null;
+        // api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
+
+        // TODO: test validations
+    }
     /**
      * test inline additionalProperties
      *
diff --git a/samples/client/petstore/java/retrofit2rx/docs/FakeApi.md b/samples/client/petstore/java/retrofit2rx/docs/FakeApi.md
index 3caa786e5ac..5335c1521aa 100644
--- a/samples/client/petstore/java/retrofit2rx/docs/FakeApi.md
+++ b/samples/client/petstore/java/retrofit2rx/docs/FakeApi.md
@@ -470,7 +470,7 @@ No authorization required
 
 <a name="testGroupParameters"></a>
 # **testGroupParameters**
-> testGroupParameters(stringGroup, booleanGroup, int64Group)
+> testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group)
 
 Fake endpoint to test group parameters (optional)
 
@@ -484,11 +484,14 @@ Fake endpoint to test group parameters (optional)
 
 
 FakeApi apiInstance = new FakeApi();
+Integer requiredStringGroup = 56; // Integer | Required String in group parameters
+Boolean requiredBooleanGroup = true; // Boolean | Required Boolean in group parameters
+Long requiredInt64Group = 56L; // Long | Required Integer in group parameters
 Integer stringGroup = 56; // Integer | String in group parameters
 Boolean booleanGroup = true; // Boolean | Boolean in group parameters
 Long int64Group = 56L; // Long | Integer in group parameters
 try {
-    apiInstance.testGroupParameters(stringGroup, booleanGroup, int64Group);
+    apiInstance.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 } catch (ApiException e) {
     System.err.println("Exception when calling FakeApi#testGroupParameters");
     e.printStackTrace();
@@ -499,6 +502,9 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **requiredStringGroup** | **Integer**| Required String in group parameters |
+ **requiredBooleanGroup** | **Boolean**| Required Boolean in group parameters |
+ **requiredInt64Group** | **Long**| Required Integer in group parameters |
  **stringGroup** | **Integer**| String in group parameters | [optional]
  **booleanGroup** | **Boolean**| Boolean in group parameters | [optional]
  **int64Group** | **Long**| Integer in group parameters | [optional]
diff --git a/samples/client/petstore/java/retrofit2rx/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/retrofit2rx/src/main/java/org/openapitools/client/api/FakeApi.java
index 09f958ecd6a..1c1f58d8c15 100644
--- a/samples/client/petstore/java/retrofit2rx/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/retrofit2rx/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -158,6 +158,9 @@ public interface FakeApi {
   /**
    * Fake endpoint to test group parameters (optional)
    * Fake endpoint to test group parameters (optional)
+   * @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)
@@ -165,7 +168,7 @@ public interface FakeApi {
    */
   @DELETE("fake")
   Observable<Void> testGroupParameters(
-    @retrofit2.http.Query("string_group") Integer stringGroup, @retrofit2.http.Header("boolean_group") Boolean booleanGroup, @retrofit2.http.Query("int64_group") Long int64Group
+    @retrofit2.http.Query("required_string_group") Integer requiredStringGroup, @retrofit2.http.Header("required_boolean_group") Boolean requiredBooleanGroup, @retrofit2.http.Query("required_int64_group") Long requiredInt64Group, @retrofit2.http.Query("string_group") Integer stringGroup, @retrofit2.http.Header("boolean_group") Boolean booleanGroup, @retrofit2.http.Query("int64_group") Long int64Group
   );
 
   /**
diff --git a/samples/client/petstore/java/retrofit2rx/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/retrofit2rx/src/test/java/org/openapitools/client/api/FakeApiTest.java
index c7caf851a43..aec2e41c34e 100644
--- a/samples/client/petstore/java/retrofit2rx/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/retrofit2rx/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -4,6 +4,7 @@ import org.openapitools.client.ApiClient;
 import java.math.BigDecimal;
 import org.openapitools.client.model.Client;
 import java.io.File;
+import org.openapitools.client.model.FileSchemaTestClass;
 import org.threeten.bp.LocalDate;
 import org.threeten.bp.OffsetDateTime;
 import org.openapitools.client.model.OuterComposite;
@@ -76,6 +77,18 @@ public class FakeApiTest {
 
         // TODO: test validations
     }
+    /**
+     * 
+     *
+     * For this test, the body for this request much reference a schema named &#x60;File&#x60;.
+     */
+    @Test
+    public void testBodyWithFileSchemaTest() {
+        FileSchemaTestClass fileSchemaTestClass = null;
+        // api.testBodyWithFileSchema(fileSchemaTestClass);
+
+        // TODO: test validations
+    }
     /**
      * 
      *
@@ -145,6 +158,23 @@ public class FakeApiTest {
 
         // TODO: test validations
     }
+    /**
+     * Fake endpoint to test group parameters (optional)
+     *
+     * Fake endpoint to test group parameters (optional)
+     */
+    @Test
+    public void testGroupParametersTest() {
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
+        Integer stringGroup = null;
+        Boolean booleanGroup = null;
+        Long int64Group = null;
+        // api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
+
+        // TODO: test validations
+    }
     /**
      * test inline additionalProperties
      *
diff --git a/samples/client/petstore/java/retrofit2rx2/docs/FakeApi.md b/samples/client/petstore/java/retrofit2rx2/docs/FakeApi.md
index 3caa786e5ac..5335c1521aa 100644
--- a/samples/client/petstore/java/retrofit2rx2/docs/FakeApi.md
+++ b/samples/client/petstore/java/retrofit2rx2/docs/FakeApi.md
@@ -470,7 +470,7 @@ No authorization required
 
 <a name="testGroupParameters"></a>
 # **testGroupParameters**
-> testGroupParameters(stringGroup, booleanGroup, int64Group)
+> testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group)
 
 Fake endpoint to test group parameters (optional)
 
@@ -484,11 +484,14 @@ Fake endpoint to test group parameters (optional)
 
 
 FakeApi apiInstance = new FakeApi();
+Integer requiredStringGroup = 56; // Integer | Required String in group parameters
+Boolean requiredBooleanGroup = true; // Boolean | Required Boolean in group parameters
+Long requiredInt64Group = 56L; // Long | Required Integer in group parameters
 Integer stringGroup = 56; // Integer | String in group parameters
 Boolean booleanGroup = true; // Boolean | Boolean in group parameters
 Long int64Group = 56L; // Long | Integer in group parameters
 try {
-    apiInstance.testGroupParameters(stringGroup, booleanGroup, int64Group);
+    apiInstance.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 } catch (ApiException e) {
     System.err.println("Exception when calling FakeApi#testGroupParameters");
     e.printStackTrace();
@@ -499,6 +502,9 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **requiredStringGroup** | **Integer**| Required String in group parameters |
+ **requiredBooleanGroup** | **Boolean**| Required Boolean in group parameters |
+ **requiredInt64Group** | **Long**| Required Integer in group parameters |
  **stringGroup** | **Integer**| String in group parameters | [optional]
  **booleanGroup** | **Boolean**| Boolean in group parameters | [optional]
  **int64Group** | **Long**| Integer in group parameters | [optional]
diff --git a/samples/client/petstore/java/retrofit2rx2/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/retrofit2rx2/src/main/java/org/openapitools/client/api/FakeApi.java
index dfdb1132524..01e20f57220 100644
--- a/samples/client/petstore/java/retrofit2rx2/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/retrofit2rx2/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -159,6 +159,9 @@ public interface FakeApi {
   /**
    * Fake endpoint to test group parameters (optional)
    * Fake endpoint to test group parameters (optional)
+   * @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)
@@ -166,7 +169,7 @@ public interface FakeApi {
    */
   @DELETE("fake")
   Completable testGroupParameters(
-    @retrofit2.http.Query("string_group") Integer stringGroup, @retrofit2.http.Header("boolean_group") Boolean booleanGroup, @retrofit2.http.Query("int64_group") Long int64Group
+    @retrofit2.http.Query("required_string_group") Integer requiredStringGroup, @retrofit2.http.Header("required_boolean_group") Boolean requiredBooleanGroup, @retrofit2.http.Query("required_int64_group") Long requiredInt64Group, @retrofit2.http.Query("string_group") Integer stringGroup, @retrofit2.http.Header("boolean_group") Boolean booleanGroup, @retrofit2.http.Query("int64_group") Long int64Group
   );
 
   /**
diff --git a/samples/client/petstore/java/retrofit2rx2/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/retrofit2rx2/src/test/java/org/openapitools/client/api/FakeApiTest.java
index c7caf851a43..aec2e41c34e 100644
--- a/samples/client/petstore/java/retrofit2rx2/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/retrofit2rx2/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -4,6 +4,7 @@ import org.openapitools.client.ApiClient;
 import java.math.BigDecimal;
 import org.openapitools.client.model.Client;
 import java.io.File;
+import org.openapitools.client.model.FileSchemaTestClass;
 import org.threeten.bp.LocalDate;
 import org.threeten.bp.OffsetDateTime;
 import org.openapitools.client.model.OuterComposite;
@@ -76,6 +77,18 @@ public class FakeApiTest {
 
         // TODO: test validations
     }
+    /**
+     * 
+     *
+     * For this test, the body for this request much reference a schema named &#x60;File&#x60;.
+     */
+    @Test
+    public void testBodyWithFileSchemaTest() {
+        FileSchemaTestClass fileSchemaTestClass = null;
+        // api.testBodyWithFileSchema(fileSchemaTestClass);
+
+        // TODO: test validations
+    }
     /**
      * 
      *
@@ -145,6 +158,23 @@ public class FakeApiTest {
 
         // TODO: test validations
     }
+    /**
+     * Fake endpoint to test group parameters (optional)
+     *
+     * Fake endpoint to test group parameters (optional)
+     */
+    @Test
+    public void testGroupParametersTest() {
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
+        Integer stringGroup = null;
+        Boolean booleanGroup = null;
+        Long int64Group = null;
+        // api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
+
+        // TODO: test validations
+    }
     /**
      * test inline additionalProperties
      *
diff --git a/samples/client/petstore/java/vertx/docs/FakeApi.md b/samples/client/petstore/java/vertx/docs/FakeApi.md
index 8ea6866dc51..34bb5172b87 100644
--- a/samples/client/petstore/java/vertx/docs/FakeApi.md
+++ b/samples/client/petstore/java/vertx/docs/FakeApi.md
@@ -470,7 +470,7 @@ No authorization required
 
 <a name="testGroupParameters"></a>
 # **testGroupParameters**
-> testGroupParameters(stringGroup, booleanGroup, int64Group)
+> testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group)
 
 Fake endpoint to test group parameters (optional)
 
@@ -484,11 +484,14 @@ Fake endpoint to test group parameters (optional)
 
 
 FakeApi apiInstance = new FakeApi();
+Integer requiredStringGroup = 56; // Integer | Required String in group parameters
+Boolean requiredBooleanGroup = true; // Boolean | Required Boolean in group parameters
+Long requiredInt64Group = 56L; // Long | Required Integer in group parameters
 Integer stringGroup = 56; // Integer | String in group parameters
 Boolean booleanGroup = true; // Boolean | Boolean in group parameters
 Long int64Group = 56L; // Long | Integer in group parameters
 try {
-    apiInstance.testGroupParameters(stringGroup, booleanGroup, int64Group);
+    apiInstance.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 } catch (ApiException e) {
     System.err.println("Exception when calling FakeApi#testGroupParameters");
     e.printStackTrace();
@@ -499,6 +502,9 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **requiredStringGroup** | **Integer**| Required String in group parameters |
+ **requiredBooleanGroup** | **Boolean**| Required Boolean in group parameters |
+ **requiredInt64Group** | **Long**| Required Integer in group parameters |
  **stringGroup** | **Integer**| String in group parameters | [optional]
  **booleanGroup** | **Boolean**| Boolean in group parameters | [optional]
  **int64Group** | **Long**| Integer in group parameters | [optional]
diff --git a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/FakeApi.java
index e95457a4270..d4349a5564e 100644
--- a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -34,7 +34,7 @@ public interface FakeApi {
 
     void testEnumParameters(List<String> enumHeaderStringArray, String enumHeaderString, List<String> enumQueryStringArray, String enumQueryString, Integer enumQueryInteger, Double enumQueryDouble, List<String> enumFormStringArray, String enumFormString, Handler<AsyncResult<Void>> handler);
 
-    void testGroupParameters(Integer stringGroup, Boolean booleanGroup, Long int64Group, Handler<AsyncResult<Void>> handler);
+    void testGroupParameters(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group, Handler<AsyncResult<Void>> handler);
 
     void testInlineAdditionalProperties(Map<String, String> requestBody, Handler<AsyncResult<Void>> handler);
 
diff --git a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/FakeApiImpl.java b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/FakeApiImpl.java
index fbc675cc003..39b3124f3a0 100644
--- a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/FakeApiImpl.java
+++ b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/FakeApiImpl.java
@@ -393,25 +393,50 @@ if (enumFormString != null) localVarFormParams.put("enum_form_string", enumFormS
     /**
      * Fake endpoint to test group parameters (optional)
      * Fake endpoint to test group parameters (optional)
+     * @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)
      * @param resultHandler Asynchronous result handler
      */
-    public void testGroupParameters(Integer stringGroup, Boolean booleanGroup, Long int64Group, Handler<AsyncResult<Void>> resultHandler) {
+    public void testGroupParameters(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group, Handler<AsyncResult<Void>> resultHandler) {
         Object localVarBody = null;
         
+        // verify the required parameter 'requiredStringGroup' is set
+        if (requiredStringGroup == null) {
+            resultHandler.handle(ApiException.fail(400, "Missing the required parameter 'requiredStringGroup' when calling testGroupParameters"));
+            return;
+        }
+        
+        // verify the required parameter 'requiredBooleanGroup' is set
+        if (requiredBooleanGroup == null) {
+            resultHandler.handle(ApiException.fail(400, "Missing the required parameter 'requiredBooleanGroup' when calling testGroupParameters"));
+            return;
+        }
+        
+        // verify the required parameter 'requiredInt64Group' is set
+        if (requiredInt64Group == null) {
+            resultHandler.handle(ApiException.fail(400, "Missing the required parameter 'requiredInt64Group' when calling testGroupParameters"));
+            return;
+        }
+        
         // create path and map variables
         String localVarPath = "/fake";
 
         // query params
         List<Pair> localVarQueryParams = new ArrayList<>();
+        localVarQueryParams.addAll(apiClient.parameterToPairs("", "required_string_group", requiredStringGroup));
+        localVarQueryParams.addAll(apiClient.parameterToPairs("", "required_int64_group", requiredInt64Group));
         localVarQueryParams.addAll(apiClient.parameterToPairs("", "string_group", stringGroup));
         localVarQueryParams.addAll(apiClient.parameterToPairs("", "int64_group", int64Group));
 
         // header params
         MultiMap localVarHeaderParams = MultiMap.caseInsensitiveMultiMap();
-        if (booleanGroup != null)
+        if (requiredBooleanGroup != null)
+        localVarHeaderParams.add("required_boolean_group", apiClient.parameterToString(requiredBooleanGroup));
+if (booleanGroup != null)
         localVarHeaderParams.add("boolean_group", apiClient.parameterToString(booleanGroup));
 
         // form params
diff --git a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/rxjava/FakeApi.java b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/rxjava/FakeApi.java
index 243a8fc4335..fce29914f89 100644
--- a/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/rxjava/FakeApi.java
+++ b/samples/client/petstore/java/vertx/src/main/java/org/openapitools/client/api/rxjava/FakeApi.java
@@ -262,26 +262,32 @@ public class FakeApi {
     /**
      * Fake endpoint to test group parameters (optional)
      * Fake endpoint to test group parameters (optional)
+     * @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)
      * @param resultHandler Asynchronous result handler
      */
-    public void testGroupParameters(Integer stringGroup, Boolean booleanGroup, Long int64Group, Handler<AsyncResult<Void>> resultHandler) {
-        delegate.testGroupParameters(stringGroup, booleanGroup, int64Group, resultHandler);
+    public void testGroupParameters(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group, Handler<AsyncResult<Void>> resultHandler) {
+        delegate.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group, resultHandler);
     }
 
     /**
      * Fake endpoint to test group parameters (optional)
      * Fake endpoint to test group parameters (optional)
+     * @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 Asynchronous result handler (RxJava Single)
      */
-    public Single<Void> rxTestGroupParameters(Integer stringGroup, Boolean booleanGroup, Long int64Group) {
+    public Single<Void> rxTestGroupParameters(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) {
         return Single.create(new io.vertx.rx.java.SingleOnSubscribeAdapter<>(fut -> {
-            delegate.testGroupParameters(stringGroup, booleanGroup, int64Group, fut);
+            delegate.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group, fut);
         }));
     }
     /**
diff --git a/samples/client/petstore/java/vertx/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/vertx/src/test/java/org/openapitools/client/api/FakeApiTest.java
index 4edda7faf91..611a4cf6149 100644
--- a/samples/client/petstore/java/vertx/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/vertx/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -15,6 +15,7 @@ package org.openapitools.client.api;
 import io.vertx.core.file.AsyncFile;
 import java.math.BigDecimal;
 import org.openapitools.client.model.Client;
+import org.openapitools.client.model.FileSchemaTestClass;
 import org.threeten.bp.LocalDate;
 import org.threeten.bp.OffsetDateTime;
 import org.openapitools.client.model.OuterComposite;
@@ -127,6 +128,22 @@ public class FakeApiTest {
         });
     }
     
+    /**
+     * 
+     * For this test, the body for this request much reference a schema named &#x60;File&#x60;.
+     *
+     * @param context Vertx test context for doing assertions
+     */
+    @Test
+    public void testBodyWithFileSchemaTest(TestContext context) {
+        Async async = context.async();
+        FileSchemaTestClass fileSchemaTestClass = null;
+        api.testBodyWithFileSchema(fileSchemaTestClass, result -> {
+            // TODO: test validations
+            async.complete();
+        });
+    }
+    
     /**
      * 
      * 
@@ -212,6 +229,27 @@ public class FakeApiTest {
         });
     }
     
+    /**
+     * Fake endpoint to test group parameters (optional)
+     * Fake endpoint to test group parameters (optional)
+     *
+     * @param context Vertx test context for doing assertions
+     */
+    @Test
+    public void testGroupParametersTest(TestContext context) {
+        Async async = context.async();
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
+        Integer stringGroup = null;
+        Boolean booleanGroup = null;
+        Long int64Group = null;
+        api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group, result -> {
+            // TODO: test validations
+            async.complete();
+        });
+    }
+    
     /**
      * test inline additionalProperties
      * 
diff --git a/samples/client/petstore/java/webclient/docs/FakeApi.md b/samples/client/petstore/java/webclient/docs/FakeApi.md
index a29ac9987a3..62046473c1f 100644
--- a/samples/client/petstore/java/webclient/docs/FakeApi.md
+++ b/samples/client/petstore/java/webclient/docs/FakeApi.md
@@ -470,7 +470,7 @@ No authorization required
 
 <a name="testGroupParameters"></a>
 # **testGroupParameters**
-> testGroupParameters(stringGroup, booleanGroup, int64Group)
+> testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group)
 
 Fake endpoint to test group parameters (optional)
 
@@ -484,11 +484,14 @@ Fake endpoint to test group parameters (optional)
 
 
 FakeApi apiInstance = new FakeApi();
+Integer requiredStringGroup = 56; // Integer | Required String in group parameters
+Boolean requiredBooleanGroup = true; // Boolean | Required Boolean in group parameters
+Long requiredInt64Group = 56L; // Long | Required Integer in group parameters
 Integer stringGroup = 56; // Integer | String in group parameters
 Boolean booleanGroup = true; // Boolean | Boolean in group parameters
 Long int64Group = 56L; // Long | Integer in group parameters
 try {
-    apiInstance.testGroupParameters(stringGroup, booleanGroup, int64Group);
+    apiInstance.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
 } catch (ApiException e) {
     System.err.println("Exception when calling FakeApi#testGroupParameters");
     e.printStackTrace();
@@ -499,6 +502,9 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **requiredStringGroup** | **Integer**| Required String in group parameters |
+ **requiredBooleanGroup** | **Boolean**| Required Boolean in group parameters |
+ **requiredInt64Group** | **Long**| Required Integer in group parameters |
  **stringGroup** | **Integer**| String in group parameters | [optional]
  **booleanGroup** | **Boolean**| Boolean in group parameters | [optional]
  **int64Group** | **Long**| Integer in group parameters | [optional]
diff --git a/samples/client/petstore/java/webclient/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/webclient/src/main/java/org/openapitools/client/api/FakeApi.java
index 091f59ea27c..a1356800406 100644
--- a/samples/client/petstore/java/webclient/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/webclient/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -424,23 +424,45 @@ public class FakeApi {
      * 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
      * @throws RestClientException if an error occurs while attempting to invoke the API
      */
-    public Mono<Void> testGroupParameters(Integer stringGroup, Boolean booleanGroup, Long int64Group) throws RestClientException {
+    public Mono<Void> testGroupParameters(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws RestClientException {
         Object postBody = null;
         
+        // verify the required parameter 'requiredStringGroup' is set
+        if (requiredStringGroup == null) {
+            throw new HttpClientErrorException(HttpStatus.BAD_REQUEST, "Missing the required parameter 'requiredStringGroup' when calling testGroupParameters");
+        }
+        
+        // verify the required parameter 'requiredBooleanGroup' is set
+        if (requiredBooleanGroup == null) {
+            throw new HttpClientErrorException(HttpStatus.BAD_REQUEST, "Missing the required parameter 'requiredBooleanGroup' when calling testGroupParameters");
+        }
+        
+        // verify the required parameter 'requiredInt64Group' is set
+        if (requiredInt64Group == null) {
+            throw new HttpClientErrorException(HttpStatus.BAD_REQUEST, "Missing the required parameter 'requiredInt64Group' when calling testGroupParameters");
+        }
+        
         String path = UriComponentsBuilder.fromPath("/fake").build().toUriString();
         
         final MultiValueMap<String, String> queryParams = new LinkedMultiValueMap<String, String>();
         final HttpHeaders headerParams = new HttpHeaders();
         final MultiValueMap<String, Object> formParams = new LinkedMultiValueMap<String, Object>();
         
+        queryParams.putAll(apiClient.parameterToMultiValueMap(null, "required_string_group", requiredStringGroup));
+        queryParams.putAll(apiClient.parameterToMultiValueMap(null, "required_int64_group", requiredInt64Group));
         queryParams.putAll(apiClient.parameterToMultiValueMap(null, "string_group", stringGroup));
         queryParams.putAll(apiClient.parameterToMultiValueMap(null, "int64_group", int64Group));
         
+        if (requiredBooleanGroup != null)
+        headerParams.add("required_boolean_group", apiClient.parameterToString(requiredBooleanGroup));
         if (booleanGroup != null)
         headerParams.add("boolean_group", apiClient.parameterToString(booleanGroup));
 
diff --git a/samples/client/petstore/java/webclient/src/test/java/org/openapitools/client/api/FakeApiTest.java b/samples/client/petstore/java/webclient/src/test/java/org/openapitools/client/api/FakeApiTest.java
index 9c1ca7fdc04..aeb8379aee7 100644
--- a/samples/client/petstore/java/webclient/src/test/java/org/openapitools/client/api/FakeApiTest.java
+++ b/samples/client/petstore/java/webclient/src/test/java/org/openapitools/client/api/FakeApiTest.java
@@ -176,6 +176,24 @@ public class FakeApiTest {
         // TODO: test validations
     }
     
+    /**
+     * Fake endpoint to test group parameters (optional)
+     *
+     * Fake endpoint to test group parameters (optional)
+     */
+    @Test
+    public void testGroupParametersTest()  {
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
+        Integer stringGroup = null;
+        Boolean booleanGroup = null;
+        Long int64Group = null;
+        api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group).block();
+
+        // TODO: test validations
+    }
+    
     /**
      * test inline additionalProperties
      *
diff --git a/samples/client/petstore/php/OpenAPIClient-php/docs/Api/FakeApi.md b/samples/client/petstore/php/OpenAPIClient-php/docs/Api/FakeApi.md
index c7c1a117fd8..c1ea9868ecc 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/docs/Api/FakeApi.md
+++ b/samples/client/petstore/php/OpenAPIClient-php/docs/Api/FakeApi.md
@@ -502,7 +502,7 @@ No authorization required
 [[Back to top]](#) [[Back to API list]](../../README.md#documentation-for-api-endpoints) [[Back to Model list]](../../README.md#documentation-for-models) [[Back to README]](../../README.md)
 
 # **testGroupParameters**
-> testGroupParameters($string_group, $boolean_group, $int64_group)
+> testGroupParameters($required_string_group, $required_boolean_group, $required_int64_group, $string_group, $boolean_group, $int64_group)
 
 Fake endpoint to test group parameters (optional)
 
@@ -518,6 +518,9 @@ $apiInstance = new OpenAPI\Client\Api\FakeApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
+$associate_array['required_string_group'] = 56; // int | Required String in group parameters
+$associate_array['required_boolean_group'] = True; // bool | Required Boolean in group parameters
+$associate_array['required_int64_group'] = 56; // int | Required Integer in group parameters
 $associate_array['string_group'] = 56; // int | String in group parameters
 $associate_array['boolean_group'] = True; // bool | Boolean in group parameters
 $associate_array['int64_group'] = 56; // int | Integer in group parameters
@@ -536,6 +539,9 @@ Note: the input parameter is an associative array with the keys listed as the pa
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **required_string_group** | **int**| Required String in group parameters |
+ **required_boolean_group** | **bool**| Required Boolean in group parameters |
+ **required_int64_group** | **int**| Required Integer in group parameters |
  **string_group** | **int**| String in group parameters | [optional]
  **boolean_group** | **bool**| Boolean in group parameters | [optional]
  **int64_group** | **int**| Integer in group parameters | [optional]
diff --git a/samples/client/petstore/php/OpenAPIClient-php/lib/Api/FakeApi.php b/samples/client/petstore/php/OpenAPIClient-php/lib/Api/FakeApi.php
index 11d71a69378..f3f1404bd2d 100644
--- a/samples/client/petstore/php/OpenAPIClient-php/lib/Api/FakeApi.php
+++ b/samples/client/petstore/php/OpenAPIClient-php/lib/Api/FakeApi.php
@@ -2524,6 +2524,9 @@ class FakeApi
      *
      * Note: the input parameter is an associative array with the keys listed as the parameter name below
      *
+     * @param  int $required_string_group Required String in group parameters (required)
+     * @param  bool $required_boolean_group Required Boolean in group parameters (required)
+     * @param  int $required_int64_group Required Integer in group parameters (required)
      * @param  int $string_group String in group parameters (optional)
      * @param  bool $boolean_group Boolean in group parameters (optional)
      * @param  int $int64_group Integer in group parameters (optional)
@@ -2544,6 +2547,9 @@ class FakeApi
      *
      * Note: the inpput parameter is an associative array with the keys listed as the parameter name below
      *
+     * @param  int $required_string_group Required String in group parameters (required)
+     * @param  bool $required_boolean_group Required Boolean in group parameters (required)
+     * @param  int $required_int64_group Required Integer in group parameters (required)
      * @param  int $string_group String in group parameters (optional)
      * @param  bool $boolean_group Boolean in group parameters (optional)
      * @param  int $int64_group Integer in group parameters (optional)
@@ -2554,7 +2560,7 @@ class FakeApi
      */
     public function testGroupParametersWithHttpInfo($associative_array)
     {
-        $request = $this->testGroupParametersRequest($associative_array['string_group'], $associative_array['boolean_group'], $associative_array['int64_group']);
+        $request = $this->testGroupParametersRequest($associative_array['required_string_group'], $associative_array['required_boolean_group'], $associative_array['required_int64_group'], $associative_array['string_group'], $associative_array['boolean_group'], $associative_array['int64_group']);
 
         try {
             $options = $this->createHttpClientOption();
@@ -2600,6 +2606,9 @@ class FakeApi
      *
      * Note: the inpput parameter is an associative array with the keys listed as the parameter name below
      *
+     * @param  int $required_string_group Required String in group parameters (required)
+     * @param  bool $required_boolean_group Required Boolean in group parameters (required)
+     * @param  int $required_int64_group Required Integer in group parameters (required)
      * @param  int $string_group String in group parameters (optional)
      * @param  bool $boolean_group Boolean in group parameters (optional)
      * @param  int $int64_group Integer in group parameters (optional)
@@ -2624,6 +2633,9 @@ class FakeApi
      *
      * Note: the inpput parameter is an associative array with the keys listed as the parameter name below
      *
+     * @param  int $required_string_group Required String in group parameters (required)
+     * @param  bool $required_boolean_group Required Boolean in group parameters (required)
+     * @param  int $required_int64_group Required Integer in group parameters (required)
      * @param  int $string_group String in group parameters (optional)
      * @param  bool $boolean_group Boolean in group parameters (optional)
      * @param  int $int64_group Integer in group parameters (optional)
@@ -2664,6 +2676,9 @@ class FakeApi
      *
      * Note: the input parameter is an associative array with the keys listed as the parameter name below
      *
+     * @param  int $required_string_group Required String in group parameters (required)
+     * @param  bool $required_boolean_group Required Boolean in group parameters (required)
+     * @param  int $required_int64_group Required Integer in group parameters (required)
      * @param  int $string_group String in group parameters (optional)
      * @param  bool $boolean_group Boolean in group parameters (optional)
      * @param  int $int64_group Integer in group parameters (optional)
@@ -2674,10 +2689,31 @@ class FakeApi
     protected function testGroupParametersRequest($associative_array)
     {
         // unbox the parameters from the associative array
+        $required_string_group = array_key_exists('required_string_group', $associative_array) ? $associative_array['required_string_group'] : null;
+        $required_boolean_group = array_key_exists('required_boolean_group', $associative_array) ? $associative_array['required_boolean_group'] : null;
+        $required_int64_group = array_key_exists('required_int64_group', $associative_array) ? $associative_array['required_int64_group'] : null;
         $string_group = array_key_exists('string_group', $associative_array) ? $associative_array['string_group'] : null;
         $boolean_group = array_key_exists('boolean_group', $associative_array) ? $associative_array['boolean_group'] : null;
         $int64_group = array_key_exists('int64_group', $associative_array) ? $associative_array['int64_group'] : null;
 
+        // verify the required parameter 'required_string_group' is set
+        if ($required_string_group === null || (is_array($required_string_group) && count($required_string_group) === 0)) {
+            throw new \InvalidArgumentException(
+                'Missing the required parameter $required_string_group when calling testGroupParameters'
+            );
+        }
+        // verify the required parameter 'required_boolean_group' is set
+        if ($required_boolean_group === null || (is_array($required_boolean_group) && count($required_boolean_group) === 0)) {
+            throw new \InvalidArgumentException(
+                'Missing the required parameter $required_boolean_group when calling testGroupParameters'
+            );
+        }
+        // verify the required parameter 'required_int64_group' is set
+        if ($required_int64_group === null || (is_array($required_int64_group) && count($required_int64_group) === 0)) {
+            throw new \InvalidArgumentException(
+                'Missing the required parameter $required_int64_group when calling testGroupParameters'
+            );
+        }
 
         $resourcePath = '/fake';
         $formParams = [];
@@ -2686,6 +2722,14 @@ class FakeApi
         $httpBody = '';
         $multipart = false;
 
+        // query params
+        if ($required_string_group !== null) {
+            $queryParams['required_string_group'] = ObjectSerializer::toQueryValue($required_string_group);
+        }
+        // query params
+        if ($required_int64_group !== null) {
+            $queryParams['required_int64_group'] = ObjectSerializer::toQueryValue($required_int64_group);
+        }
         // query params
         if ($string_group !== null) {
             $queryParams['string_group'] = ObjectSerializer::toQueryValue($string_group);
@@ -2695,6 +2739,10 @@ class FakeApi
             $queryParams['int64_group'] = ObjectSerializer::toQueryValue($int64_group);
         }
         // header params
+        if ($required_boolean_group !== null) {
+            $headerParams['required_boolean_group'] = ObjectSerializer::toHeaderValue($required_boolean_group);
+        }
+        // header params
         if ($boolean_group !== null) {
             $headerParams['boolean_group'] = ObjectSerializer::toHeaderValue($boolean_group);
         }
diff --git a/samples/client/petstore/ruby/docs/FakeApi.md b/samples/client/petstore/ruby/docs/FakeApi.md
index 59edb6114f8..3a26c4926c1 100644
--- a/samples/client/petstore/ruby/docs/FakeApi.md
+++ b/samples/client/petstore/ruby/docs/FakeApi.md
@@ -472,7 +472,7 @@ No authorization required
 
 
 # **test_group_parameters**
-> test_group_parameters(opts)
+> test_group_parameters(required_string_group, required_boolean_group, required_int64_group, opts)
 
 Fake endpoint to test group parameters (optional)
 
@@ -484,6 +484,9 @@ Fake endpoint to test group parameters (optional)
 require 'petstore'
 
 api_instance = Petstore::FakeApi.new
+required_string_group = 56 # Integer | Required String in group parameters
+required_boolean_group = true # BOOLEAN | Required Boolean in group parameters
+required_int64_group = 56 # Integer | Required Integer in group parameters
 opts = {
   string_group: 56, # Integer | String in group parameters
   boolean_group: true, # BOOLEAN | Boolean in group parameters
@@ -492,7 +495,7 @@ opts = {
 
 begin
   #Fake endpoint to test group parameters (optional)
-  api_instance.test_group_parameters(opts)
+  api_instance.test_group_parameters(required_string_group, required_boolean_group, required_int64_group, opts)
 rescue Petstore::ApiError => e
   puts "Exception when calling FakeApi->test_group_parameters: #{e}"
 end
@@ -502,6 +505,9 @@ end
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **required_string_group** | **Integer**| Required String in group parameters | 
+ **required_boolean_group** | **BOOLEAN**| Required Boolean in group parameters | 
+ **required_int64_group** | **Integer**| Required Integer in group parameters | 
  **string_group** | **Integer**| String in group parameters | [optional] 
  **boolean_group** | **BOOLEAN**| Boolean in group parameters | [optional] 
  **int64_group** | **Integer**| Integer in group parameters | [optional] 
diff --git a/samples/client/petstore/ruby/lib/petstore/api/fake_api.rb b/samples/client/petstore/ruby/lib/petstore/api/fake_api.rb
index 05843a31952..dd13c6540fe 100644
--- a/samples/client/petstore/ruby/lib/petstore/api/fake_api.rb
+++ b/samples/client/petstore/ruby/lib/petstore/api/fake_api.rb
@@ -627,37 +627,58 @@ module Petstore
 
     # Fake endpoint to test group parameters (optional)
     # Fake endpoint to test group parameters (optional)
+    # @param required_string_group Required String in group parameters
+    # @param required_boolean_group Required Boolean in group parameters
+    # @param required_int64_group Required Integer in group parameters
     # @param [Hash] opts the optional parameters
     # @option opts [Integer] :string_group String in group parameters
     # @option opts [BOOLEAN] :boolean_group Boolean in group parameters
     # @option opts [Integer] :int64_group Integer in group parameters
     # @return [nil]
-    def test_group_parameters(opts = {})
-      test_group_parameters_with_http_info(opts)
+    def test_group_parameters(required_string_group, required_boolean_group, required_int64_group, opts = {})
+      test_group_parameters_with_http_info(required_string_group, required_boolean_group, required_int64_group, opts)
       nil
     end
 
     # Fake endpoint to test group parameters (optional)
     # Fake endpoint to test group parameters (optional)
+    # @param required_string_group Required String in group parameters
+    # @param required_boolean_group Required Boolean in group parameters
+    # @param required_int64_group Required Integer in group parameters
     # @param [Hash] opts the optional parameters
     # @option opts [Integer] :string_group String in group parameters
     # @option opts [BOOLEAN] :boolean_group Boolean in group parameters
     # @option opts [Integer] :int64_group Integer in group parameters
     # @return [Array<(nil, Fixnum, Hash)>] nil, response status code and response headers
-    def test_group_parameters_with_http_info(opts = {})
+    def test_group_parameters_with_http_info(required_string_group, required_boolean_group, required_int64_group, opts = {})
       if @api_client.config.debugging
         @api_client.config.logger.debug 'Calling API: FakeApi.test_group_parameters ...'
       end
+      # verify the required parameter 'required_string_group' is set
+      if @api_client.config.client_side_validation && required_string_group.nil?
+        fail ArgumentError, "Missing the required parameter 'required_string_group' when calling FakeApi.test_group_parameters"
+      end
+      # verify the required parameter 'required_boolean_group' is set
+      if @api_client.config.client_side_validation && required_boolean_group.nil?
+        fail ArgumentError, "Missing the required parameter 'required_boolean_group' when calling FakeApi.test_group_parameters"
+      end
+      # verify the required parameter 'required_int64_group' is set
+      if @api_client.config.client_side_validation && required_int64_group.nil?
+        fail ArgumentError, "Missing the required parameter 'required_int64_group' when calling FakeApi.test_group_parameters"
+      end
       # resource path
       local_var_path = '/fake'
 
       # query parameters
       query_params = {}
+      query_params[:'required_string_group'] = required_string_group
+      query_params[:'required_int64_group'] = required_int64_group
       query_params[:'string_group'] = opts[:'string_group'] if !opts[:'string_group'].nil?
       query_params[:'int64_group'] = opts[:'int64_group'] if !opts[:'int64_group'].nil?
 
       # header parameters
       header_params = {}
+      header_params[:'required_boolean_group'] = required_boolean_group
       header_params[:'boolean_group'] = opts[:'boolean_group'] if !opts[:'boolean_group'].nil?
 
       # form parameters
diff --git a/samples/openapi3/client/petstore/php/OpenAPIClient-php/docs/Api/FakeApi.md b/samples/openapi3/client/petstore/php/OpenAPIClient-php/docs/Api/FakeApi.md
index e3d7f5e2051..d428bf33f0b 100644
--- a/samples/openapi3/client/petstore/php/OpenAPIClient-php/docs/Api/FakeApi.md
+++ b/samples/openapi3/client/petstore/php/OpenAPIClient-php/docs/Api/FakeApi.md
@@ -502,7 +502,7 @@ No authorization required
 [[Back to top]](#) [[Back to API list]](../../README.md#documentation-for-api-endpoints) [[Back to Model list]](../../README.md#documentation-for-models) [[Back to README]](../../README.md)
 
 # **testGroupParameters**
-> testGroupParameters($string_group, $boolean_group, $int64_group)
+> testGroupParameters($required_string_group, $required_boolean_group, $required_int64_group, $string_group, $boolean_group, $int64_group)
 
 Fake endpoint to test group parameters (optional)
 
@@ -518,6 +518,9 @@ $apiInstance = new OpenAPI\Client\Api\FakeApi(
     // This is optional, `GuzzleHttp\Client` will be used as default.
     new GuzzleHttp\Client()
 );
+$associate_array['required_string_group'] = 56; // int | Required String in group parameters
+$associate_array['required_boolean_group'] = True; // bool | Required Boolean in group parameters
+$associate_array['required_int64_group'] = 56; // int | Required Integer in group parameters
 $associate_array['string_group'] = 56; // int | String in group parameters
 $associate_array['boolean_group'] = True; // bool | Boolean in group parameters
 $associate_array['int64_group'] = 56; // int | Integer in group parameters
@@ -536,6 +539,9 @@ Note: the input parameter is an associative array with the keys listed as the pa
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
+ **required_string_group** | **int**| Required String in group parameters |
+ **required_boolean_group** | **bool**| Required Boolean in group parameters |
+ **required_int64_group** | **int**| Required Integer in group parameters |
  **string_group** | **int**| String in group parameters | [optional]
  **boolean_group** | **bool**| Boolean in group parameters | [optional]
  **int64_group** | **int**| Integer in group parameters | [optional]
diff --git a/samples/openapi3/client/petstore/php/OpenAPIClient-php/lib/Api/FakeApi.php b/samples/openapi3/client/petstore/php/OpenAPIClient-php/lib/Api/FakeApi.php
index fe2920a3c0c..3b2a198a771 100644
--- a/samples/openapi3/client/petstore/php/OpenAPIClient-php/lib/Api/FakeApi.php
+++ b/samples/openapi3/client/petstore/php/OpenAPIClient-php/lib/Api/FakeApi.php
@@ -2524,6 +2524,9 @@ class FakeApi
      *
      * Note: the input parameter is an associative array with the keys listed as the parameter name below
      *
+     * @param  int $required_string_group Required String in group parameters (required)
+     * @param  bool $required_boolean_group Required Boolean in group parameters (required)
+     * @param  int $required_int64_group Required Integer in group parameters (required)
      * @param  int $string_group String in group parameters (optional)
      * @param  bool $boolean_group Boolean in group parameters (optional)
      * @param  int $int64_group Integer in group parameters (optional)
@@ -2544,6 +2547,9 @@ class FakeApi
      *
      * Note: the inpput parameter is an associative array with the keys listed as the parameter name below
      *
+     * @param  int $required_string_group Required String in group parameters (required)
+     * @param  bool $required_boolean_group Required Boolean in group parameters (required)
+     * @param  int $required_int64_group Required Integer in group parameters (required)
      * @param  int $string_group String in group parameters (optional)
      * @param  bool $boolean_group Boolean in group parameters (optional)
      * @param  int $int64_group Integer in group parameters (optional)
@@ -2554,7 +2560,7 @@ class FakeApi
      */
     public function testGroupParametersWithHttpInfo($associative_array)
     {
-        $request = $this->testGroupParametersRequest($associative_array['string_group'], $associative_array['boolean_group'], $associative_array['int64_group']);
+        $request = $this->testGroupParametersRequest($associative_array['required_string_group'], $associative_array['required_boolean_group'], $associative_array['required_int64_group'], $associative_array['string_group'], $associative_array['boolean_group'], $associative_array['int64_group']);
 
         try {
             $options = $this->createHttpClientOption();
@@ -2600,6 +2606,9 @@ class FakeApi
      *
      * Note: the inpput parameter is an associative array with the keys listed as the parameter name below
      *
+     * @param  int $required_string_group Required String in group parameters (required)
+     * @param  bool $required_boolean_group Required Boolean in group parameters (required)
+     * @param  int $required_int64_group Required Integer in group parameters (required)
      * @param  int $string_group String in group parameters (optional)
      * @param  bool $boolean_group Boolean in group parameters (optional)
      * @param  int $int64_group Integer in group parameters (optional)
@@ -2624,6 +2633,9 @@ class FakeApi
      *
      * Note: the inpput parameter is an associative array with the keys listed as the parameter name below
      *
+     * @param  int $required_string_group Required String in group parameters (required)
+     * @param  bool $required_boolean_group Required Boolean in group parameters (required)
+     * @param  int $required_int64_group Required Integer in group parameters (required)
      * @param  int $string_group String in group parameters (optional)
      * @param  bool $boolean_group Boolean in group parameters (optional)
      * @param  int $int64_group Integer in group parameters (optional)
@@ -2664,6 +2676,9 @@ class FakeApi
      *
      * Note: the input parameter is an associative array with the keys listed as the parameter name below
      *
+     * @param  int $required_string_group Required String in group parameters (required)
+     * @param  bool $required_boolean_group Required Boolean in group parameters (required)
+     * @param  int $required_int64_group Required Integer in group parameters (required)
      * @param  int $string_group String in group parameters (optional)
      * @param  bool $boolean_group Boolean in group parameters (optional)
      * @param  int $int64_group Integer in group parameters (optional)
@@ -2674,10 +2689,31 @@ class FakeApi
     protected function testGroupParametersRequest($associative_array)
     {
         // unbox the parameters from the associative array
+        $required_string_group = array_key_exists('required_string_group', $associative_array) ? $associative_array['required_string_group'] : null;
+        $required_boolean_group = array_key_exists('required_boolean_group', $associative_array) ? $associative_array['required_boolean_group'] : null;
+        $required_int64_group = array_key_exists('required_int64_group', $associative_array) ? $associative_array['required_int64_group'] : null;
         $string_group = array_key_exists('string_group', $associative_array) ? $associative_array['string_group'] : null;
         $boolean_group = array_key_exists('boolean_group', $associative_array) ? $associative_array['boolean_group'] : null;
         $int64_group = array_key_exists('int64_group', $associative_array) ? $associative_array['int64_group'] : null;
 
+        // verify the required parameter 'required_string_group' is set
+        if ($required_string_group === null || (is_array($required_string_group) && count($required_string_group) === 0)) {
+            throw new \InvalidArgumentException(
+                'Missing the required parameter $required_string_group when calling testGroupParameters'
+            );
+        }
+        // verify the required parameter 'required_boolean_group' is set
+        if ($required_boolean_group === null || (is_array($required_boolean_group) && count($required_boolean_group) === 0)) {
+            throw new \InvalidArgumentException(
+                'Missing the required parameter $required_boolean_group when calling testGroupParameters'
+            );
+        }
+        // verify the required parameter 'required_int64_group' is set
+        if ($required_int64_group === null || (is_array($required_int64_group) && count($required_int64_group) === 0)) {
+            throw new \InvalidArgumentException(
+                'Missing the required parameter $required_int64_group when calling testGroupParameters'
+            );
+        }
 
         $resourcePath = '/fake';
         $formParams = [];
@@ -2686,6 +2722,14 @@ class FakeApi
         $httpBody = '';
         $multipart = false;
 
+        // query params
+        if ($required_string_group !== null) {
+            $queryParams['required_string_group'] = ObjectSerializer::toQueryValue($required_string_group);
+        }
+        // query params
+        if ($required_int64_group !== null) {
+            $queryParams['required_int64_group'] = ObjectSerializer::toQueryValue($required_int64_group);
+        }
         // query params
         if ($string_group !== null) {
             $queryParams['string_group'] = ObjectSerializer::toQueryValue($string_group);
@@ -2695,6 +2739,10 @@ class FakeApi
             $queryParams['int64_group'] = ObjectSerializer::toQueryValue($int64_group);
         }
         // header params
+        if ($required_boolean_group !== null) {
+            $headerParams['required_boolean_group'] = ObjectSerializer::toHeaderValue($required_boolean_group);
+        }
+        // header params
         if ($boolean_group !== null) {
             $headerParams['boolean_group'] = ObjectSerializer::toHeaderValue($boolean_group);
         }
diff --git a/samples/server/petstore/jaxrs-cxf/src/gen/java/org/openapitools/api/FakeApi.java b/samples/server/petstore/jaxrs-cxf/src/gen/java/org/openapitools/api/FakeApi.java
index b212f1c67d1..0bd54724ded 100644
--- a/samples/server/petstore/jaxrs-cxf/src/gen/java/org/openapitools/api/FakeApi.java
+++ b/samples/server/petstore/jaxrs-cxf/src/gen/java/org/openapitools/api/FakeApi.java
@@ -141,7 +141,7 @@ public interface FakeApi  {
     @ApiOperation(value = "Fake endpoint to test group parameters (optional)", tags={ "fake",  })
     @ApiResponses(value = { 
         @ApiResponse(code = 400, message = "Someting wrong") })
-    public void testGroupParameters(@QueryParam("string_group") Integer stringGroup, @HeaderParam("boolean_group") Boolean booleanGroup, @QueryParam("int64_group") Long int64Group);
+    public void testGroupParameters(@QueryParam("required_string_group") @NotNull Integer requiredStringGroup, @HeaderParam("required_boolean_group") Boolean requiredBooleanGroup, @QueryParam("required_int64_group") @NotNull Long requiredInt64Group, @QueryParam("string_group") Integer stringGroup, @HeaderParam("boolean_group") Boolean booleanGroup, @QueryParam("int64_group") Long int64Group);
 
     /**
      * test inline additionalProperties
diff --git a/samples/server/petstore/jaxrs-cxf/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java b/samples/server/petstore/jaxrs-cxf/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java
index 812581c5b14..061e7112d55 100644
--- a/samples/server/petstore/jaxrs-cxf/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java
+++ b/samples/server/petstore/jaxrs-cxf/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java
@@ -109,7 +109,7 @@ public class FakeApiServiceImpl implements FakeApi {
      * Fake endpoint to test group parameters (optional)
      *
      */
-    public void testGroupParameters(Integer stringGroup, Boolean booleanGroup, Long int64Group) {
+    public void testGroupParameters(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) {
         // TODO: Implement...
         
         
diff --git a/samples/server/petstore/jaxrs-cxf/src/test/java/org/openapitools/api/FakeApiTest.java b/samples/server/petstore/jaxrs-cxf/src/test/java/org/openapitools/api/FakeApiTest.java
index b476e5528d0..5816222f1e7 100644
--- a/samples/server/petstore/jaxrs-cxf/src/test/java/org/openapitools/api/FakeApiTest.java
+++ b/samples/server/petstore/jaxrs-cxf/src/test/java/org/openapitools/api/FakeApiTest.java
@@ -248,10 +248,13 @@ public class FakeApiTest {
      */
     @Test
     public void testGroupParametersTest() {
+        Integer requiredStringGroup = null;
+        Boolean requiredBooleanGroup = null;
+        Long requiredInt64Group = null;
         Integer stringGroup = null;
         Boolean booleanGroup = null;
         Long int64Group = null;
-        //api.testGroupParameters(stringGroup, booleanGroup, int64Group);
+        //api.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
         
         // TODO: test validations
         
diff --git a/samples/server/petstore/jaxrs-datelib-j8/src/gen/java/org/openapitools/api/FakeApi.java b/samples/server/petstore/jaxrs-datelib-j8/src/gen/java/org/openapitools/api/FakeApi.java
index a8db12b2afc..a872ff17f4e 100644
--- a/samples/server/petstore/jaxrs-datelib-j8/src/gen/java/org/openapitools/api/FakeApi.java
+++ b/samples/server/petstore/jaxrs-datelib-j8/src/gen/java/org/openapitools/api/FakeApi.java
@@ -208,12 +208,15 @@ public class FakeApi  {
     @io.swagger.annotations.ApiOperation(value = "Fake endpoint to test group parameters (optional)", notes = "Fake endpoint to test group parameters (optional)", response = Void.class, tags={ "fake", })
     @io.swagger.annotations.ApiResponses(value = { 
         @io.swagger.annotations.ApiResponse(code = 400, message = "Someting wrong", response = Void.class) })
-    public Response testGroupParameters(@ApiParam(value = "String in group parameters") @QueryParam("string_group") Integer stringGroup
+    public Response testGroupParameters(@ApiParam(value = "Required String in group parameters",required=true) @QueryParam("required_string_group") Integer requiredStringGroup
+,@ApiParam(value = "Required Boolean in group parameters" ,required=true)@HeaderParam("required_boolean_group") Boolean requiredBooleanGroup
+,@ApiParam(value = "Required Integer in group parameters",required=true) @QueryParam("required_int64_group") Long requiredInt64Group
+,@ApiParam(value = "String in group parameters") @QueryParam("string_group") Integer stringGroup
 ,@ApiParam(value = "Boolean in group parameters" )@HeaderParam("boolean_group") Boolean booleanGroup
 ,@ApiParam(value = "Integer in group parameters") @QueryParam("int64_group") Long int64Group
 ,@Context SecurityContext securityContext)
     throws NotFoundException {
-        return delegate.testGroupParameters(stringGroup,booleanGroup,int64Group,securityContext);
+        return delegate.testGroupParameters(requiredStringGroup,requiredBooleanGroup,requiredInt64Group,stringGroup,booleanGroup,int64Group,securityContext);
     }
     @POST
     @Path("/inline-additionalProperties")
diff --git a/samples/server/petstore/jaxrs-datelib-j8/src/gen/java/org/openapitools/api/FakeApiService.java b/samples/server/petstore/jaxrs-datelib-j8/src/gen/java/org/openapitools/api/FakeApiService.java
index fbf3fc75bc5..fc90d3b8e1a 100644
--- a/samples/server/petstore/jaxrs-datelib-j8/src/gen/java/org/openapitools/api/FakeApiService.java
+++ b/samples/server/petstore/jaxrs-datelib-j8/src/gen/java/org/openapitools/api/FakeApiService.java
@@ -35,7 +35,7 @@ public abstract class FakeApiService {
     public abstract Response testClientModel(Client client,SecurityContext securityContext) throws NotFoundException;
     public abstract Response testEndpointParameters(BigDecimal number,Double _double,String patternWithoutDelimiter,byte[] _byte,Integer integer,Integer int32,Long int64,Float _float,String string,InputStream binaryInputStream, FormDataContentDisposition binaryDetail,LocalDate date,OffsetDateTime dateTime,String password,String paramCallback,SecurityContext securityContext) throws NotFoundException;
     public abstract Response testEnumParameters(List<String> enumHeaderStringArray,String enumHeaderString, List<String> enumQueryStringArray, String enumQueryString, Integer enumQueryInteger, Double enumQueryDouble,List<String> enumFormStringArray,String enumFormString,SecurityContext securityContext) throws NotFoundException;
-    public abstract Response testGroupParameters( Integer stringGroup,Boolean booleanGroup, Long int64Group,SecurityContext securityContext) throws NotFoundException;
+    public abstract Response testGroupParameters( @NotNull Integer requiredStringGroup,Boolean requiredBooleanGroup, @NotNull Long requiredInt64Group, Integer stringGroup,Boolean booleanGroup, Long int64Group,SecurityContext securityContext) throws NotFoundException;
     public abstract Response testInlineAdditionalProperties(Map<String, String> requestBody,SecurityContext securityContext) throws NotFoundException;
     public abstract Response testJsonFormData(String param,String param2,SecurityContext securityContext) throws NotFoundException;
     public abstract Response uploadFileWithRequiredFile(Long petId,InputStream requiredFileInputStream, FormDataContentDisposition requiredFileDetail,String additionalMetadata,SecurityContext securityContext) throws NotFoundException;
diff --git a/samples/server/petstore/jaxrs-datelib-j8/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java b/samples/server/petstore/jaxrs-datelib-j8/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java
index 52d6b276ae4..b608ee79159 100644
--- a/samples/server/petstore/jaxrs-datelib-j8/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java
+++ b/samples/server/petstore/jaxrs-datelib-j8/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java
@@ -72,7 +72,7 @@ public class FakeApiServiceImpl extends FakeApiService {
         return Response.ok().entity(new ApiResponseMessage(ApiResponseMessage.OK, "magic!")).build();
     }
     @Override
-    public Response testGroupParameters( Integer stringGroup, Boolean booleanGroup,  Long int64Group, SecurityContext securityContext) throws NotFoundException {
+    public Response testGroupParameters( @NotNull Integer requiredStringGroup, Boolean requiredBooleanGroup,  @NotNull Long requiredInt64Group,  Integer stringGroup, Boolean booleanGroup,  Long int64Group, SecurityContext securityContext) throws NotFoundException {
         // do some magic!
         return Response.ok().entity(new ApiResponseMessage(ApiResponseMessage.OK, "magic!")).build();
     }
diff --git a/samples/server/petstore/jaxrs-jersey/src/gen/java/org/openapitools/api/FakeApi.java b/samples/server/petstore/jaxrs-jersey/src/gen/java/org/openapitools/api/FakeApi.java
index 304ddc3d28c..c47f03f0462 100644
--- a/samples/server/petstore/jaxrs-jersey/src/gen/java/org/openapitools/api/FakeApi.java
+++ b/samples/server/petstore/jaxrs-jersey/src/gen/java/org/openapitools/api/FakeApi.java
@@ -207,12 +207,15 @@ public class FakeApi  {
     @io.swagger.annotations.ApiOperation(value = "Fake endpoint to test group parameters (optional)", notes = "Fake endpoint to test group parameters (optional)", response = Void.class, tags={ "fake", })
     @io.swagger.annotations.ApiResponses(value = { 
         @io.swagger.annotations.ApiResponse(code = 400, message = "Someting wrong", response = Void.class) })
-    public Response testGroupParameters(@ApiParam(value = "String in group parameters") @QueryParam("string_group") Integer stringGroup
+    public Response testGroupParameters(@ApiParam(value = "Required String in group parameters",required=true) @QueryParam("required_string_group") Integer requiredStringGroup
+,@ApiParam(value = "Required Boolean in group parameters" ,required=true)@HeaderParam("required_boolean_group") Boolean requiredBooleanGroup
+,@ApiParam(value = "Required Integer in group parameters",required=true) @QueryParam("required_int64_group") Long requiredInt64Group
+,@ApiParam(value = "String in group parameters") @QueryParam("string_group") Integer stringGroup
 ,@ApiParam(value = "Boolean in group parameters" )@HeaderParam("boolean_group") Boolean booleanGroup
 ,@ApiParam(value = "Integer in group parameters") @QueryParam("int64_group") Long int64Group
 ,@Context SecurityContext securityContext)
     throws NotFoundException {
-        return delegate.testGroupParameters(stringGroup,booleanGroup,int64Group,securityContext);
+        return delegate.testGroupParameters(requiredStringGroup,requiredBooleanGroup,requiredInt64Group,stringGroup,booleanGroup,int64Group,securityContext);
     }
     @POST
     @Path("/inline-additionalProperties")
diff --git a/samples/server/petstore/jaxrs-jersey/src/gen/java/org/openapitools/api/FakeApiService.java b/samples/server/petstore/jaxrs-jersey/src/gen/java/org/openapitools/api/FakeApiService.java
index 8ea44f5923d..9319d058951 100644
--- a/samples/server/petstore/jaxrs-jersey/src/gen/java/org/openapitools/api/FakeApiService.java
+++ b/samples/server/petstore/jaxrs-jersey/src/gen/java/org/openapitools/api/FakeApiService.java
@@ -34,7 +34,7 @@ public abstract class FakeApiService {
     public abstract Response testClientModel(Client client,SecurityContext securityContext) throws NotFoundException;
     public abstract Response testEndpointParameters(BigDecimal number,Double _double,String patternWithoutDelimiter,byte[] _byte,Integer integer,Integer int32,Long int64,Float _float,String string,InputStream binaryInputStream, FormDataContentDisposition binaryDetail,Date date,Date dateTime,String password,String paramCallback,SecurityContext securityContext) throws NotFoundException;
     public abstract Response testEnumParameters(List<String> enumHeaderStringArray,String enumHeaderString, List<String> enumQueryStringArray, String enumQueryString, Integer enumQueryInteger, Double enumQueryDouble,List<String> enumFormStringArray,String enumFormString,SecurityContext securityContext) throws NotFoundException;
-    public abstract Response testGroupParameters( Integer stringGroup,Boolean booleanGroup, Long int64Group,SecurityContext securityContext) throws NotFoundException;
+    public abstract Response testGroupParameters( @NotNull Integer requiredStringGroup,Boolean requiredBooleanGroup, @NotNull Long requiredInt64Group, Integer stringGroup,Boolean booleanGroup, Long int64Group,SecurityContext securityContext) throws NotFoundException;
     public abstract Response testInlineAdditionalProperties(Map<String, String> requestBody,SecurityContext securityContext) throws NotFoundException;
     public abstract Response testJsonFormData(String param,String param2,SecurityContext securityContext) throws NotFoundException;
     public abstract Response uploadFileWithRequiredFile(Long petId,InputStream requiredFileInputStream, FormDataContentDisposition requiredFileDetail,String additionalMetadata,SecurityContext securityContext) throws NotFoundException;
diff --git a/samples/server/petstore/jaxrs-jersey/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java b/samples/server/petstore/jaxrs-jersey/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java
index 37288374e7f..d771656bb35 100644
--- a/samples/server/petstore/jaxrs-jersey/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java
+++ b/samples/server/petstore/jaxrs-jersey/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java
@@ -71,7 +71,7 @@ public class FakeApiServiceImpl extends FakeApiService {
         return Response.ok().entity(new ApiResponseMessage(ApiResponseMessage.OK, "magic!")).build();
     }
     @Override
-    public Response testGroupParameters( Integer stringGroup, Boolean booleanGroup,  Long int64Group, SecurityContext securityContext) throws NotFoundException {
+    public Response testGroupParameters( @NotNull Integer requiredStringGroup, Boolean requiredBooleanGroup,  @NotNull Long requiredInt64Group,  Integer stringGroup, Boolean booleanGroup,  Long int64Group, SecurityContext securityContext) throws NotFoundException {
         // do some magic!
         return Response.ok().entity(new ApiResponseMessage(ApiResponseMessage.OK, "magic!")).build();
     }
diff --git a/samples/server/petstore/jaxrs-spec-interface/src/gen/java/org/openapitools/api/FakeApi.java b/samples/server/petstore/jaxrs-spec-interface/src/gen/java/org/openapitools/api/FakeApi.java
index b8cd7c76872..0827c2758d1 100644
--- a/samples/server/petstore/jaxrs-spec-interface/src/gen/java/org/openapitools/api/FakeApi.java
+++ b/samples/server/petstore/jaxrs-spec-interface/src/gen/java/org/openapitools/api/FakeApi.java
@@ -104,7 +104,7 @@ public interface FakeApi {
     @ApiOperation(value = "Fake endpoint to test group parameters (optional)", notes = "Fake endpoint to test group parameters (optional)", tags={ "fake",  })
     @ApiResponses(value = { 
         @ApiResponse(code = 400, message = "Someting wrong", response = Void.class) })
-    void testGroupParameters(@QueryParam("string_group")   @ApiParam("String in group parameters")  Integer stringGroup,@HeaderParam("boolean_group")   @ApiParam("Boolean in group parameters") Boolean booleanGroup,@QueryParam("int64_group")   @ApiParam("Integer in group parameters")  Long int64Group);
+    void testGroupParameters(@QueryParam("required_string_group") @NotNull   @ApiParam("Required String in group parameters")  Integer requiredStringGroup,@HeaderParam("required_boolean_group") @NotNull   @ApiParam("Required Boolean in group parameters") Boolean requiredBooleanGroup,@QueryParam("required_int64_group") @NotNull   @ApiParam("Required Integer in group parameters")  Long requiredInt64Group,@QueryParam("string_group")   @ApiParam("String in group parameters")  Integer stringGroup,@HeaderParam("boolean_group")   @ApiParam("Boolean in group parameters") Boolean booleanGroup,@QueryParam("int64_group")   @ApiParam("Integer in group parameters")  Long int64Group);
 
     @POST
     @Path("/inline-additionalProperties")
diff --git a/samples/server/petstore/jaxrs-spec-interface/src/main/openapi/openapi.yaml b/samples/server/petstore/jaxrs-spec-interface/src/main/openapi/openapi.yaml
index 799de419314..7aaa0e0a18b 100644
--- a/samples/server/petstore/jaxrs-spec-interface/src/main/openapi/openapi.yaml
+++ b/samples/server/petstore/jaxrs-spec-interface/src/main/openapi/openapi.yaml
@@ -635,6 +635,25 @@ paths:
       description: Fake endpoint to test group parameters (optional)
       operationId: testGroupParameters
       parameters:
+      - description: Required String in group parameters
+        in: query
+        name: required_string_group
+        required: true
+        schema:
+          type: integer
+      - description: Required Boolean in group parameters
+        in: header
+        name: required_boolean_group
+        required: true
+        schema:
+          type: boolean
+      - description: Required Integer in group parameters
+        in: query
+        name: required_int64_group
+        required: true
+        schema:
+          format: int64
+          type: integer
       - description: String in group parameters
         in: query
         name: string_group
diff --git a/samples/server/petstore/jaxrs-spec/src/gen/java/org/openapitools/api/FakeApi.java b/samples/server/petstore/jaxrs-spec/src/gen/java/org/openapitools/api/FakeApi.java
index 80e6cee3985..a5ed5461ef8 100644
--- a/samples/server/petstore/jaxrs-spec/src/gen/java/org/openapitools/api/FakeApi.java
+++ b/samples/server/petstore/jaxrs-spec/src/gen/java/org/openapitools/api/FakeApi.java
@@ -132,7 +132,7 @@ public class FakeApi {
     @ApiResponses(value = { 
         @ApiResponse(code = 400, message = "Someting wrong", response = Void.class)
     })
-    public Response testGroupParameters(@QueryParam("string_group")   @ApiParam("String in group parameters")  Integer stringGroup,@HeaderParam("boolean_group")   @ApiParam("Boolean in group parameters") Boolean booleanGroup,@QueryParam("int64_group")   @ApiParam("Integer in group parameters")  Long int64Group) {
+    public Response testGroupParameters(@QueryParam("required_string_group") @NotNull   @ApiParam("Required String in group parameters")  Integer requiredStringGroup,@HeaderParam("required_boolean_group") @NotNull   @ApiParam("Required Boolean in group parameters") Boolean requiredBooleanGroup,@QueryParam("required_int64_group") @NotNull   @ApiParam("Required Integer in group parameters")  Long requiredInt64Group,@QueryParam("string_group")   @ApiParam("String in group parameters")  Integer stringGroup,@HeaderParam("boolean_group")   @ApiParam("Boolean in group parameters") Boolean booleanGroup,@QueryParam("int64_group")   @ApiParam("Integer in group parameters")  Long int64Group) {
         return Response.ok().entity("magic!").build();
     }
 
diff --git a/samples/server/petstore/jaxrs-spec/src/main/openapi/openapi.yaml b/samples/server/petstore/jaxrs-spec/src/main/openapi/openapi.yaml
index 799de419314..7aaa0e0a18b 100644
--- a/samples/server/petstore/jaxrs-spec/src/main/openapi/openapi.yaml
+++ b/samples/server/petstore/jaxrs-spec/src/main/openapi/openapi.yaml
@@ -635,6 +635,25 @@ paths:
       description: Fake endpoint to test group parameters (optional)
       operationId: testGroupParameters
       parameters:
+      - description: Required String in group parameters
+        in: query
+        name: required_string_group
+        required: true
+        schema:
+          type: integer
+      - description: Required Boolean in group parameters
+        in: header
+        name: required_boolean_group
+        required: true
+        schema:
+          type: boolean
+      - description: Required Integer in group parameters
+        in: query
+        name: required_int64_group
+        required: true
+        schema:
+          format: int64
+          type: integer
       - description: String in group parameters
         in: query
         name: string_group
diff --git a/samples/server/petstore/jaxrs/jersey1-useTags/src/gen/java/org/openapitools/api/FakeApi.java b/samples/server/petstore/jaxrs/jersey1-useTags/src/gen/java/org/openapitools/api/FakeApi.java
index 916ba073b33..a7d6b517654 100644
--- a/samples/server/petstore/jaxrs/jersey1-useTags/src/gen/java/org/openapitools/api/FakeApi.java
+++ b/samples/server/petstore/jaxrs/jersey1-useTags/src/gen/java/org/openapitools/api/FakeApi.java
@@ -191,12 +191,15 @@ public class FakeApi  {
     @io.swagger.annotations.ApiResponses(value = { 
         @io.swagger.annotations.ApiResponse(code = 400, message = "Someting wrong", response = Void.class) })
     public Response testGroupParameters(
+        @ApiParam(value = "Required String in group parameters",required=true) @QueryParam("required_string_group") Integer requiredStringGroup,
+        @ApiParam(value = "Required Boolean in group parameters" ,required=true)@HeaderParam("required_boolean_group") Boolean requiredBooleanGroup,
+        @ApiParam(value = "Required Integer in group parameters",required=true) @QueryParam("required_int64_group") Long requiredInt64Group,
         @ApiParam(value = "String in group parameters") @QueryParam("string_group") Integer stringGroup,
         @ApiParam(value = "Boolean in group parameters" )@HeaderParam("boolean_group") Boolean booleanGroup,
         @ApiParam(value = "Integer in group parameters") @QueryParam("int64_group") Long int64Group,
         @Context SecurityContext securityContext)
     throws NotFoundException {
-        return delegate.testGroupParameters(stringGroup,booleanGroup,int64Group,securityContext);
+        return delegate.testGroupParameters(requiredStringGroup,requiredBooleanGroup,requiredInt64Group,stringGroup,booleanGroup,int64Group,securityContext);
     }
     @POST
     @Path("/inline-additionalProperties")
diff --git a/samples/server/petstore/jaxrs/jersey1-useTags/src/gen/java/org/openapitools/api/FakeApiService.java b/samples/server/petstore/jaxrs/jersey1-useTags/src/gen/java/org/openapitools/api/FakeApiService.java
index 55f5a5257d0..fed55467984 100644
--- a/samples/server/petstore/jaxrs/jersey1-useTags/src/gen/java/org/openapitools/api/FakeApiService.java
+++ b/samples/server/petstore/jaxrs/jersey1-useTags/src/gen/java/org/openapitools/api/FakeApiService.java
@@ -45,7 +45,7 @@ public abstract class FakeApiService {
       throws NotFoundException;
       public abstract Response testEnumParameters(List<String> enumHeaderStringArray,String enumHeaderString, List<String> enumQueryStringArray, String enumQueryString, Integer enumQueryInteger, Double enumQueryDouble,List<String> enumFormStringArray,String enumFormString,SecurityContext securityContext)
       throws NotFoundException;
-      public abstract Response testGroupParameters( Integer stringGroup,Boolean booleanGroup, Long int64Group,SecurityContext securityContext)
+      public abstract Response testGroupParameters( @NotNull Integer requiredStringGroup,Boolean requiredBooleanGroup, @NotNull Long requiredInt64Group, Integer stringGroup,Boolean booleanGroup, Long int64Group,SecurityContext securityContext)
       throws NotFoundException;
       public abstract Response testInlineAdditionalProperties(Map<String, String> requestBody,SecurityContext securityContext)
       throws NotFoundException;
diff --git a/samples/server/petstore/jaxrs/jersey1-useTags/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java b/samples/server/petstore/jaxrs/jersey1-useTags/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java
index ae4238f4d82..6c0a98ec53a 100644
--- a/samples/server/petstore/jaxrs/jersey1-useTags/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java
+++ b/samples/server/petstore/jaxrs/jersey1-useTags/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java
@@ -82,7 +82,7 @@ public class FakeApiServiceImpl extends FakeApiService {
         return Response.ok().entity(new ApiResponseMessage(ApiResponseMessage.OK, "magic!")).build();
     }
     @Override
-    public Response testGroupParameters( Integer stringGroup, Boolean booleanGroup,  Long int64Group, SecurityContext securityContext)
+    public Response testGroupParameters( @NotNull Integer requiredStringGroup, Boolean requiredBooleanGroup,  @NotNull Long requiredInt64Group,  Integer stringGroup, Boolean booleanGroup,  Long int64Group, SecurityContext securityContext)
     throws NotFoundException {
         // do some magic!
         return Response.ok().entity(new ApiResponseMessage(ApiResponseMessage.OK, "magic!")).build();
diff --git a/samples/server/petstore/jaxrs/jersey1/src/gen/java/org/openapitools/api/FakeApi.java b/samples/server/petstore/jaxrs/jersey1/src/gen/java/org/openapitools/api/FakeApi.java
index 80d3018bcad..192e2fdc1c8 100644
--- a/samples/server/petstore/jaxrs/jersey1/src/gen/java/org/openapitools/api/FakeApi.java
+++ b/samples/server/petstore/jaxrs/jersey1/src/gen/java/org/openapitools/api/FakeApi.java
@@ -192,12 +192,15 @@ public class FakeApi  {
     @io.swagger.annotations.ApiResponses(value = { 
         @io.swagger.annotations.ApiResponse(code = 400, message = "Someting wrong", response = Void.class) })
     public Response testGroupParameters(
+        @ApiParam(value = "Required String in group parameters",required=true) @QueryParam("required_string_group") Integer requiredStringGroup,
+        @ApiParam(value = "Required Boolean in group parameters" ,required=true)@HeaderParam("required_boolean_group") Boolean requiredBooleanGroup,
+        @ApiParam(value = "Required Integer in group parameters",required=true) @QueryParam("required_int64_group") Long requiredInt64Group,
         @ApiParam(value = "String in group parameters") @QueryParam("string_group") Integer stringGroup,
         @ApiParam(value = "Boolean in group parameters" )@HeaderParam("boolean_group") Boolean booleanGroup,
         @ApiParam(value = "Integer in group parameters") @QueryParam("int64_group") Long int64Group,
         @Context SecurityContext securityContext)
     throws NotFoundException {
-        return delegate.testGroupParameters(stringGroup,booleanGroup,int64Group,securityContext);
+        return delegate.testGroupParameters(requiredStringGroup,requiredBooleanGroup,requiredInt64Group,stringGroup,booleanGroup,int64Group,securityContext);
     }
     @POST
     @Path("/inline-additionalProperties")
diff --git a/samples/server/petstore/jaxrs/jersey1/src/gen/java/org/openapitools/api/FakeApiService.java b/samples/server/petstore/jaxrs/jersey1/src/gen/java/org/openapitools/api/FakeApiService.java
index 20f05383f60..143287741bd 100644
--- a/samples/server/petstore/jaxrs/jersey1/src/gen/java/org/openapitools/api/FakeApiService.java
+++ b/samples/server/petstore/jaxrs/jersey1/src/gen/java/org/openapitools/api/FakeApiService.java
@@ -46,7 +46,7 @@ public abstract class FakeApiService {
       throws NotFoundException;
       public abstract Response testEnumParameters(List<String> enumHeaderStringArray,String enumHeaderString, List<String> enumQueryStringArray, String enumQueryString, Integer enumQueryInteger, Double enumQueryDouble,List<String> enumFormStringArray,String enumFormString,SecurityContext securityContext)
       throws NotFoundException;
-      public abstract Response testGroupParameters( Integer stringGroup,Boolean booleanGroup, Long int64Group,SecurityContext securityContext)
+      public abstract Response testGroupParameters( @NotNull Integer requiredStringGroup,Boolean requiredBooleanGroup, @NotNull Long requiredInt64Group, Integer stringGroup,Boolean booleanGroup, Long int64Group,SecurityContext securityContext)
       throws NotFoundException;
       public abstract Response testInlineAdditionalProperties(Map<String, String> requestBody,SecurityContext securityContext)
       throws NotFoundException;
diff --git a/samples/server/petstore/jaxrs/jersey1/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java b/samples/server/petstore/jaxrs/jersey1/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java
index 6861c8607aa..e2c2e189cac 100644
--- a/samples/server/petstore/jaxrs/jersey1/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java
+++ b/samples/server/petstore/jaxrs/jersey1/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java
@@ -83,7 +83,7 @@ public class FakeApiServiceImpl extends FakeApiService {
         return Response.ok().entity(new ApiResponseMessage(ApiResponseMessage.OK, "magic!")).build();
     }
     @Override
-    public Response testGroupParameters( Integer stringGroup, Boolean booleanGroup,  Long int64Group, SecurityContext securityContext)
+    public Response testGroupParameters( @NotNull Integer requiredStringGroup, Boolean requiredBooleanGroup,  @NotNull Long requiredInt64Group,  Integer stringGroup, Boolean booleanGroup,  Long int64Group, SecurityContext securityContext)
     throws NotFoundException {
         // do some magic!
         return Response.ok().entity(new ApiResponseMessage(ApiResponseMessage.OK, "magic!")).build();
diff --git a/samples/server/petstore/jaxrs/jersey2-useTags/src/gen/java/org/openapitools/api/FakeApi.java b/samples/server/petstore/jaxrs/jersey2-useTags/src/gen/java/org/openapitools/api/FakeApi.java
index 57b8c57a76b..0dc93668755 100644
--- a/samples/server/petstore/jaxrs/jersey2-useTags/src/gen/java/org/openapitools/api/FakeApi.java
+++ b/samples/server/petstore/jaxrs/jersey2-useTags/src/gen/java/org/openapitools/api/FakeApi.java
@@ -206,12 +206,15 @@ public class FakeApi  {
     @io.swagger.annotations.ApiOperation(value = "Fake endpoint to test group parameters (optional)", notes = "Fake endpoint to test group parameters (optional)", response = Void.class, tags={ "fake", })
     @io.swagger.annotations.ApiResponses(value = { 
         @io.swagger.annotations.ApiResponse(code = 400, message = "Someting wrong", response = Void.class) })
-    public Response testGroupParameters(@ApiParam(value = "String in group parameters") @QueryParam("string_group") Integer stringGroup
+    public Response testGroupParameters(@ApiParam(value = "Required String in group parameters",required=true) @QueryParam("required_string_group") Integer requiredStringGroup
+,@ApiParam(value = "Required Boolean in group parameters" ,required=true)@HeaderParam("required_boolean_group") Boolean requiredBooleanGroup
+,@ApiParam(value = "Required Integer in group parameters",required=true) @QueryParam("required_int64_group") Long requiredInt64Group
+,@ApiParam(value = "String in group parameters") @QueryParam("string_group") Integer stringGroup
 ,@ApiParam(value = "Boolean in group parameters" )@HeaderParam("boolean_group") Boolean booleanGroup
 ,@ApiParam(value = "Integer in group parameters") @QueryParam("int64_group") Long int64Group
 ,@Context SecurityContext securityContext)
     throws NotFoundException {
-        return delegate.testGroupParameters(stringGroup,booleanGroup,int64Group,securityContext);
+        return delegate.testGroupParameters(requiredStringGroup,requiredBooleanGroup,requiredInt64Group,stringGroup,booleanGroup,int64Group,securityContext);
     }
     @POST
     @Path("/inline-additionalProperties")
diff --git a/samples/server/petstore/jaxrs/jersey2-useTags/src/gen/java/org/openapitools/api/FakeApiService.java b/samples/server/petstore/jaxrs/jersey2-useTags/src/gen/java/org/openapitools/api/FakeApiService.java
index d7e2031b5b5..febdb0d1a6d 100644
--- a/samples/server/petstore/jaxrs/jersey2-useTags/src/gen/java/org/openapitools/api/FakeApiService.java
+++ b/samples/server/petstore/jaxrs/jersey2-useTags/src/gen/java/org/openapitools/api/FakeApiService.java
@@ -33,7 +33,7 @@ public abstract class FakeApiService {
     public abstract Response testClientModel(Client client,SecurityContext securityContext) throws NotFoundException;
     public abstract Response testEndpointParameters(BigDecimal number,Double _double,String patternWithoutDelimiter,byte[] _byte,Integer integer,Integer int32,Long int64,Float _float,String string,InputStream binaryInputStream, FormDataContentDisposition binaryDetail,Date date,Date dateTime,String password,String paramCallback,SecurityContext securityContext) throws NotFoundException;
     public abstract Response testEnumParameters(List<String> enumHeaderStringArray,String enumHeaderString, List<String> enumQueryStringArray, String enumQueryString, Integer enumQueryInteger, Double enumQueryDouble,List<String> enumFormStringArray,String enumFormString,SecurityContext securityContext) throws NotFoundException;
-    public abstract Response testGroupParameters( Integer stringGroup,Boolean booleanGroup, Long int64Group,SecurityContext securityContext) throws NotFoundException;
+    public abstract Response testGroupParameters( @NotNull Integer requiredStringGroup,Boolean requiredBooleanGroup, @NotNull Long requiredInt64Group, Integer stringGroup,Boolean booleanGroup, Long int64Group,SecurityContext securityContext) throws NotFoundException;
     public abstract Response testInlineAdditionalProperties(Map<String, String> requestBody,SecurityContext securityContext) throws NotFoundException;
     public abstract Response testJsonFormData(String param,String param2,SecurityContext securityContext) throws NotFoundException;
 }
diff --git a/samples/server/petstore/jaxrs/jersey2-useTags/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java b/samples/server/petstore/jaxrs/jersey2-useTags/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java
index fa4bb591ee6..862ccc6b7d0 100644
--- a/samples/server/petstore/jaxrs/jersey2-useTags/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java
+++ b/samples/server/petstore/jaxrs/jersey2-useTags/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java
@@ -70,7 +70,7 @@ public class FakeApiServiceImpl extends FakeApiService {
         return Response.ok().entity(new ApiResponseMessage(ApiResponseMessage.OK, "magic!")).build();
     }
     @Override
-    public Response testGroupParameters( Integer stringGroup, Boolean booleanGroup,  Long int64Group, SecurityContext securityContext) throws NotFoundException {
+    public Response testGroupParameters( @NotNull Integer requiredStringGroup, Boolean requiredBooleanGroup,  @NotNull Long requiredInt64Group,  Integer stringGroup, Boolean booleanGroup,  Long int64Group, SecurityContext securityContext) throws NotFoundException {
         // do some magic!
         return Response.ok().entity(new ApiResponseMessage(ApiResponseMessage.OK, "magic!")).build();
     }
diff --git a/samples/server/petstore/jaxrs/jersey2/src/gen/java/org/openapitools/api/FakeApi.java b/samples/server/petstore/jaxrs/jersey2/src/gen/java/org/openapitools/api/FakeApi.java
index 16131c7596c..986a66be5a2 100644
--- a/samples/server/petstore/jaxrs/jersey2/src/gen/java/org/openapitools/api/FakeApi.java
+++ b/samples/server/petstore/jaxrs/jersey2/src/gen/java/org/openapitools/api/FakeApi.java
@@ -207,12 +207,15 @@ public class FakeApi  {
     @io.swagger.annotations.ApiOperation(value = "Fake endpoint to test group parameters (optional)", notes = "Fake endpoint to test group parameters (optional)", response = Void.class, tags={ "fake", })
     @io.swagger.annotations.ApiResponses(value = { 
         @io.swagger.annotations.ApiResponse(code = 400, message = "Someting wrong", response = Void.class) })
-    public Response testGroupParameters(@ApiParam(value = "String in group parameters") @QueryParam("string_group") Integer stringGroup
+    public Response testGroupParameters(@ApiParam(value = "Required String in group parameters",required=true) @QueryParam("required_string_group") Integer requiredStringGroup
+,@ApiParam(value = "Required Boolean in group parameters" ,required=true)@HeaderParam("required_boolean_group") Boolean requiredBooleanGroup
+,@ApiParam(value = "Required Integer in group parameters",required=true) @QueryParam("required_int64_group") Long requiredInt64Group
+,@ApiParam(value = "String in group parameters") @QueryParam("string_group") Integer stringGroup
 ,@ApiParam(value = "Boolean in group parameters" )@HeaderParam("boolean_group") Boolean booleanGroup
 ,@ApiParam(value = "Integer in group parameters") @QueryParam("int64_group") Long int64Group
 ,@Context SecurityContext securityContext)
     throws NotFoundException {
-        return delegate.testGroupParameters(stringGroup,booleanGroup,int64Group,securityContext);
+        return delegate.testGroupParameters(requiredStringGroup,requiredBooleanGroup,requiredInt64Group,stringGroup,booleanGroup,int64Group,securityContext);
     }
     @POST
     @Path("/inline-additionalProperties")
diff --git a/samples/server/petstore/jaxrs/jersey2/src/gen/java/org/openapitools/api/FakeApiService.java b/samples/server/petstore/jaxrs/jersey2/src/gen/java/org/openapitools/api/FakeApiService.java
index 8ea44f5923d..9319d058951 100644
--- a/samples/server/petstore/jaxrs/jersey2/src/gen/java/org/openapitools/api/FakeApiService.java
+++ b/samples/server/petstore/jaxrs/jersey2/src/gen/java/org/openapitools/api/FakeApiService.java
@@ -34,7 +34,7 @@ public abstract class FakeApiService {
     public abstract Response testClientModel(Client client,SecurityContext securityContext) throws NotFoundException;
     public abstract Response testEndpointParameters(BigDecimal number,Double _double,String patternWithoutDelimiter,byte[] _byte,Integer integer,Integer int32,Long int64,Float _float,String string,InputStream binaryInputStream, FormDataContentDisposition binaryDetail,Date date,Date dateTime,String password,String paramCallback,SecurityContext securityContext) throws NotFoundException;
     public abstract Response testEnumParameters(List<String> enumHeaderStringArray,String enumHeaderString, List<String> enumQueryStringArray, String enumQueryString, Integer enumQueryInteger, Double enumQueryDouble,List<String> enumFormStringArray,String enumFormString,SecurityContext securityContext) throws NotFoundException;
-    public abstract Response testGroupParameters( Integer stringGroup,Boolean booleanGroup, Long int64Group,SecurityContext securityContext) throws NotFoundException;
+    public abstract Response testGroupParameters( @NotNull Integer requiredStringGroup,Boolean requiredBooleanGroup, @NotNull Long requiredInt64Group, Integer stringGroup,Boolean booleanGroup, Long int64Group,SecurityContext securityContext) throws NotFoundException;
     public abstract Response testInlineAdditionalProperties(Map<String, String> requestBody,SecurityContext securityContext) throws NotFoundException;
     public abstract Response testJsonFormData(String param,String param2,SecurityContext securityContext) throws NotFoundException;
     public abstract Response uploadFileWithRequiredFile(Long petId,InputStream requiredFileInputStream, FormDataContentDisposition requiredFileDetail,String additionalMetadata,SecurityContext securityContext) throws NotFoundException;
diff --git a/samples/server/petstore/jaxrs/jersey2/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java b/samples/server/petstore/jaxrs/jersey2/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java
index 37288374e7f..d771656bb35 100644
--- a/samples/server/petstore/jaxrs/jersey2/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java
+++ b/samples/server/petstore/jaxrs/jersey2/src/main/java/org/openapitools/api/impl/FakeApiServiceImpl.java
@@ -71,7 +71,7 @@ public class FakeApiServiceImpl extends FakeApiService {
         return Response.ok().entity(new ApiResponseMessage(ApiResponseMessage.OK, "magic!")).build();
     }
     @Override
-    public Response testGroupParameters( Integer stringGroup, Boolean booleanGroup,  Long int64Group, SecurityContext securityContext) throws NotFoundException {
+    public Response testGroupParameters( @NotNull Integer requiredStringGroup, Boolean requiredBooleanGroup,  @NotNull Long requiredInt64Group,  Integer stringGroup, Boolean booleanGroup,  Long int64Group, SecurityContext securityContext) throws NotFoundException {
         // do some magic!
         return Response.ok().entity(new ApiResponseMessage(ApiResponseMessage.OK, "magic!")).build();
     }
diff --git a/samples/server/petstore/php-lumen/lib/app/Http/Controllers/FakeApi.php b/samples/server/petstore/php-lumen/lib/app/Http/Controllers/FakeApi.php
index decfebfb5f7..fd3261ab546 100644
--- a/samples/server/petstore/php-lumen/lib/app/Http/Controllers/FakeApi.php
+++ b/samples/server/petstore/php-lumen/lib/app/Http/Controllers/FakeApi.php
@@ -199,6 +199,21 @@ class FakeApi extends Controller
 
 
         //not path params validation
+        if (!isset($input['required_string_group'])) {
+            throw new \InvalidArgumentException('Missing the required parameter $required_string_group when calling testGroupParameters');
+        }
+        $required_string_group = $input['required_string_group'];
+
+        if (!isset($input['required_boolean_group'])) {
+            throw new \InvalidArgumentException('Missing the required parameter $required_boolean_group when calling testGroupParameters');
+        }
+        $required_boolean_group = $input['required_boolean_group'];
+
+        if (!isset($input['required_int64_group'])) {
+            throw new \InvalidArgumentException('Missing the required parameter $required_int64_group when calling testGroupParameters');
+        }
+        $required_int64_group = $input['required_int64_group'];
+
         $string_group = $input['string_group'];
 
         $boolean_group = $input['boolean_group'];
diff --git a/samples/server/petstore/php-slim/lib/Api/FakeApi.php b/samples/server/petstore/php-slim/lib/Api/FakeApi.php
index 5934463100a..d6dd7958c8f 100644
--- a/samples/server/petstore/php-slim/lib/Api/FakeApi.php
+++ b/samples/server/petstore/php-slim/lib/Api/FakeApi.php
@@ -218,8 +218,11 @@ class FakeApi extends AbstractApiController
     public function testGroupParameters($request, $response, $args)
     {
         $headers = $request->getHeaders();
+        $requiredBooleanGroup = $request->hasHeader('required_boolean_group') ? $headers['required_boolean_group'] : null;
         $booleanGroup = $request->hasHeader('boolean_group') ? $headers['boolean_group'] : null;
         $queryParams = $request->getQueryParams();
+        $requiredStringGroup = $request->getQueryParam('required_string_group');
+        $requiredInt64Group = $request->getQueryParam('required_int64_group');
         $stringGroup = $request->getQueryParam('string_group');
         $int64Group = $request->getQueryParam('int64_group');
         $response->write('How about implementing testGroupParameters as a DELETE method ?');
diff --git a/samples/server/petstore/spring-mvc-j8-async/src/main/java/org/openapitools/api/FakeApi.java b/samples/server/petstore/spring-mvc-j8-async/src/main/java/org/openapitools/api/FakeApi.java
index 740684c9c49..3d2219c1a40 100644
--- a/samples/server/petstore/spring-mvc-j8-async/src/main/java/org/openapitools/api/FakeApi.java
+++ b/samples/server/petstore/spring-mvc-j8-async/src/main/java/org/openapitools/api/FakeApi.java
@@ -183,7 +183,7 @@ public interface FakeApi {
         @ApiResponse(code = 400, message = "Someting wrong") })
     @RequestMapping(value = "/fake",
         method = RequestMethod.DELETE)
-    default CompletableFuture<ResponseEntity<Void>> testGroupParameters(@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group) {
+    default CompletableFuture<ResponseEntity<Void>> testGroupParameters(@NotNull @ApiParam(value = "Required String in group parameters", required = true) @Valid @RequestParam(value = "required_string_group", required = true) Integer requiredStringGroup,@ApiParam(value = "Required Boolean in group parameters" ,required=true) @RequestHeader(value="required_boolean_group", required=true) Boolean requiredBooleanGroup,@NotNull @ApiParam(value = "Required Integer in group parameters", required = true) @Valid @RequestParam(value = "required_int64_group", required = true) Long requiredInt64Group,@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group) {
         return CompletableFuture.completedFuture(new ResponseEntity<>(HttpStatus.NOT_IMPLEMENTED));
 
     }
diff --git a/samples/server/petstore/spring-mvc-j8-localdatetime/src/main/java/org/openapitools/api/FakeApi.java b/samples/server/petstore/spring-mvc-j8-localdatetime/src/main/java/org/openapitools/api/FakeApi.java
index 34474fb2f7e..73d426743f9 100644
--- a/samples/server/petstore/spring-mvc-j8-localdatetime/src/main/java/org/openapitools/api/FakeApi.java
+++ b/samples/server/petstore/spring-mvc-j8-localdatetime/src/main/java/org/openapitools/api/FakeApi.java
@@ -178,7 +178,7 @@ public interface FakeApi {
         @ApiResponse(code = 400, message = "Someting wrong") })
     @RequestMapping(value = "/fake",
         method = RequestMethod.DELETE)
-    default ResponseEntity<Void> testGroupParameters(@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group) {
+    default ResponseEntity<Void> testGroupParameters(@NotNull @ApiParam(value = "Required String in group parameters", required = true) @Valid @RequestParam(value = "required_string_group", required = true) Integer requiredStringGroup,@ApiParam(value = "Required Boolean in group parameters" ,required=true) @RequestHeader(value="required_boolean_group", required=true) Boolean requiredBooleanGroup,@NotNull @ApiParam(value = "Required Integer in group parameters", required = true) @Valid @RequestParam(value = "required_int64_group", required = true) Long requiredInt64Group,@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group) {
         return new ResponseEntity<>(HttpStatus.NOT_IMPLEMENTED);
 
     }
diff --git a/samples/server/petstore/spring-mvc/src/main/java/org/openapitools/api/FakeApi.java b/samples/server/petstore/spring-mvc/src/main/java/org/openapitools/api/FakeApi.java
index 80d658308bb..c24a3440068 100644
--- a/samples/server/petstore/spring-mvc/src/main/java/org/openapitools/api/FakeApi.java
+++ b/samples/server/petstore/spring-mvc/src/main/java/org/openapitools/api/FakeApi.java
@@ -127,7 +127,7 @@ public interface FakeApi {
         @ApiResponse(code = 400, message = "Someting wrong") })
     @RequestMapping(value = "/fake",
         method = RequestMethod.DELETE)
-    ResponseEntity<Void> testGroupParameters(@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group);
+    ResponseEntity<Void> testGroupParameters(@NotNull @ApiParam(value = "Required String in group parameters", required = true) @Valid @RequestParam(value = "required_string_group", required = true) Integer requiredStringGroup,@ApiParam(value = "Required Boolean in group parameters" ,required=true) @RequestHeader(value="required_boolean_group", required=true) Boolean requiredBooleanGroup,@NotNull @ApiParam(value = "Required Integer in group parameters", required = true) @Valid @RequestParam(value = "required_int64_group", required = true) Long requiredInt64Group,@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group);
 
 
     @ApiOperation(value = "test inline additionalProperties", nickname = "testInlineAdditionalProperties", notes = "", tags={ "fake", })
diff --git a/samples/server/petstore/spring-mvc/src/main/java/org/openapitools/api/FakeApiController.java b/samples/server/petstore/spring-mvc/src/main/java/org/openapitools/api/FakeApiController.java
index 98b54389e3a..a4991d3e5f1 100644
--- a/samples/server/petstore/spring-mvc/src/main/java/org/openapitools/api/FakeApiController.java
+++ b/samples/server/petstore/spring-mvc/src/main/java/org/openapitools/api/FakeApiController.java
@@ -97,7 +97,7 @@ public class FakeApiController implements FakeApi {
 
     }
 
-    public ResponseEntity<Void> testGroupParameters(@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group) {
+    public ResponseEntity<Void> testGroupParameters(@NotNull @ApiParam(value = "Required String in group parameters", required = true) @Valid @RequestParam(value = "required_string_group", required = true) Integer requiredStringGroup,@ApiParam(value = "Required Boolean in group parameters" ,required=true) @RequestHeader(value="required_boolean_group", required=true) Boolean requiredBooleanGroup,@NotNull @ApiParam(value = "Required Integer in group parameters", required = true) @Valid @RequestParam(value = "required_int64_group", required = true) Long requiredInt64Group,@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group) {
         return new ResponseEntity<>(HttpStatus.NOT_IMPLEMENTED);
 
     }
diff --git a/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/api/FakeApi.java b/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/api/FakeApi.java
index 80d658308bb..c24a3440068 100644
--- a/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/api/FakeApi.java
+++ b/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/api/FakeApi.java
@@ -127,7 +127,7 @@ public interface FakeApi {
         @ApiResponse(code = 400, message = "Someting wrong") })
     @RequestMapping(value = "/fake",
         method = RequestMethod.DELETE)
-    ResponseEntity<Void> testGroupParameters(@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group);
+    ResponseEntity<Void> testGroupParameters(@NotNull @ApiParam(value = "Required String in group parameters", required = true) @Valid @RequestParam(value = "required_string_group", required = true) Integer requiredStringGroup,@ApiParam(value = "Required Boolean in group parameters" ,required=true) @RequestHeader(value="required_boolean_group", required=true) Boolean requiredBooleanGroup,@NotNull @ApiParam(value = "Required Integer in group parameters", required = true) @Valid @RequestParam(value = "required_int64_group", required = true) Long requiredInt64Group,@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group);
 
 
     @ApiOperation(value = "test inline additionalProperties", nickname = "testInlineAdditionalProperties", notes = "", tags={ "fake", })
diff --git a/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/api/FakeApiController.java b/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/api/FakeApiController.java
index 7981d705578..c3369289623 100644
--- a/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/api/FakeApiController.java
+++ b/samples/server/petstore/springboot-beanvalidation/src/main/java/org/openapitools/api/FakeApiController.java
@@ -97,7 +97,7 @@ public class FakeApiController implements FakeApi {
 
     }
 
-    public ResponseEntity<Void> testGroupParameters(@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group) {
+    public ResponseEntity<Void> testGroupParameters(@NotNull @ApiParam(value = "Required String in group parameters", required = true) @Valid @RequestParam(value = "required_string_group", required = true) Integer requiredStringGroup,@ApiParam(value = "Required Boolean in group parameters" ,required=true) @RequestHeader(value="required_boolean_group", required=true) Boolean requiredBooleanGroup,@NotNull @ApiParam(value = "Required Integer in group parameters", required = true) @Valid @RequestParam(value = "required_int64_group", required = true) Long requiredInt64Group,@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group) {
         return new ResponseEntity<>(HttpStatus.NOT_IMPLEMENTED);
 
     }
diff --git a/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/api/FakeApi.java b/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/api/FakeApi.java
index 1cfd6cdbdf5..0dbb0526a53 100644
--- a/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/api/FakeApi.java
+++ b/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/api/FakeApi.java
@@ -149,8 +149,8 @@ public interface FakeApi {
         @ApiResponse(code = 400, message = "Someting wrong") })
     @RequestMapping(value = "/fake",
         method = RequestMethod.DELETE)
-    default ResponseEntity<Void> testGroupParameters(@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group) {
-        return getDelegate().testGroupParameters(stringGroup, booleanGroup, int64Group);
+    default ResponseEntity<Void> testGroupParameters(@NotNull @ApiParam(value = "Required String in group parameters", required = true) @Valid @RequestParam(value = "required_string_group", required = true) Integer requiredStringGroup,@ApiParam(value = "Required Boolean in group parameters" ,required=true) @RequestHeader(value="required_boolean_group", required=true) Boolean requiredBooleanGroup,@NotNull @ApiParam(value = "Required Integer in group parameters", required = true) @Valid @RequestParam(value = "required_int64_group", required = true) Long requiredInt64Group,@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group) {
+        return getDelegate().testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
     }
 
 
diff --git a/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/api/FakeApiDelegate.java b/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/api/FakeApiDelegate.java
index 2694060b724..9c0f4d8375d 100644
--- a/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/api/FakeApiDelegate.java
+++ b/samples/server/petstore/springboot-delegate-j8/src/main/java/org/openapitools/api/FakeApiDelegate.java
@@ -144,7 +144,10 @@ public interface FakeApiDelegate {
     /**
      * @see FakeApi#testGroupParameters
      */
-    default ResponseEntity<Void> testGroupParameters(Integer stringGroup,
+    default ResponseEntity<Void> testGroupParameters(Integer requiredStringGroup,
+        Boolean requiredBooleanGroup,
+        Long requiredInt64Group,
+        Integer stringGroup,
         Boolean booleanGroup,
         Long int64Group) {
         return new ResponseEntity<>(HttpStatus.NOT_IMPLEMENTED);
diff --git a/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/api/FakeApi.java b/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/api/FakeApi.java
index 80d658308bb..c24a3440068 100644
--- a/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/api/FakeApi.java
+++ b/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/api/FakeApi.java
@@ -127,7 +127,7 @@ public interface FakeApi {
         @ApiResponse(code = 400, message = "Someting wrong") })
     @RequestMapping(value = "/fake",
         method = RequestMethod.DELETE)
-    ResponseEntity<Void> testGroupParameters(@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group);
+    ResponseEntity<Void> testGroupParameters(@NotNull @ApiParam(value = "Required String in group parameters", required = true) @Valid @RequestParam(value = "required_string_group", required = true) Integer requiredStringGroup,@ApiParam(value = "Required Boolean in group parameters" ,required=true) @RequestHeader(value="required_boolean_group", required=true) Boolean requiredBooleanGroup,@NotNull @ApiParam(value = "Required Integer in group parameters", required = true) @Valid @RequestParam(value = "required_int64_group", required = true) Long requiredInt64Group,@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group);
 
 
     @ApiOperation(value = "test inline additionalProperties", nickname = "testInlineAdditionalProperties", notes = "", tags={ "fake", })
diff --git a/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/api/FakeApiController.java b/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/api/FakeApiController.java
index 41ebeb12176..9d4ef3e8206 100644
--- a/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/api/FakeApiController.java
+++ b/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/api/FakeApiController.java
@@ -74,8 +74,8 @@ public class FakeApiController implements FakeApi {
         return delegate.testEnumParameters(enumHeaderStringArray, enumHeaderString, enumQueryStringArray, enumQueryString, enumQueryInteger, enumQueryDouble, enumFormStringArray, enumFormString);
     }
 
-    public ResponseEntity<Void> testGroupParameters(@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group) {
-        return delegate.testGroupParameters(stringGroup, booleanGroup, int64Group);
+    public ResponseEntity<Void> testGroupParameters(@NotNull @ApiParam(value = "Required String in group parameters", required = true) @Valid @RequestParam(value = "required_string_group", required = true) Integer requiredStringGroup,@ApiParam(value = "Required Boolean in group parameters" ,required=true) @RequestHeader(value="required_boolean_group", required=true) Boolean requiredBooleanGroup,@NotNull @ApiParam(value = "Required Integer in group parameters", required = true) @Valid @RequestParam(value = "required_int64_group", required = true) Long requiredInt64Group,@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group) {
+        return delegate.testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group);
     }
 
     public ResponseEntity<Void> testInlineAdditionalProperties(@ApiParam(value = "request body" ,required=true )  @Valid @RequestBody Map<String, String> requestBody) {
diff --git a/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/api/FakeApiDelegate.java b/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/api/FakeApiDelegate.java
index cd84bcec314..64d24f36c56 100644
--- a/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/api/FakeApiDelegate.java
+++ b/samples/server/petstore/springboot-delegate/src/main/java/org/openapitools/api/FakeApiDelegate.java
@@ -93,7 +93,10 @@ public interface FakeApiDelegate {
     /**
      * @see FakeApi#testGroupParameters
      */
-    ResponseEntity<Void> testGroupParameters(Integer stringGroup,
+    ResponseEntity<Void> testGroupParameters(Integer requiredStringGroup,
+        Boolean requiredBooleanGroup,
+        Long requiredInt64Group,
+        Integer stringGroup,
         Boolean booleanGroup,
         Long int64Group);
 
diff --git a/samples/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/api/FakeApi.java b/samples/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/api/FakeApi.java
index a33bc5dbb0d..509cf98165a 100644
--- a/samples/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/api/FakeApi.java
+++ b/samples/server/petstore/springboot-implicitHeaders/src/main/java/org/openapitools/api/FakeApi.java
@@ -197,11 +197,12 @@ public interface FakeApi {
     @ApiResponses(value = { 
         @ApiResponse(code = 400, message = "Someting wrong") })
     @ApiImplicitParams({
+    @ApiImplicitParam(name = "requiredBooleanGroup", value = "Required Boolean in group parameters", required=true, dataType = "Boolean", paramType = "header"),
     @ApiImplicitParam(name = "booleanGroup", value = "Boolean in group parameters",  dataType = "Boolean", paramType = "header")
     })
     @RequestMapping(value = "/fake",
         method = RequestMethod.DELETE)
-    default ResponseEntity<Void> testGroupParameters(@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group) {
+    default ResponseEntity<Void> testGroupParameters(@NotNull @ApiParam(value = "Required String in group parameters", required = true) @Valid @RequestParam(value = "required_string_group", required = true) Integer requiredStringGroup,@NotNull @ApiParam(value = "Required Integer in group parameters", required = true) @Valid @RequestParam(value = "required_int64_group", required = true) Long requiredInt64Group,@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group) {
         return new ResponseEntity<>(HttpStatus.NOT_IMPLEMENTED);
 
     }
diff --git a/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/api/FakeApi.java b/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/api/FakeApi.java
index 2111513f467..a027b932a3c 100644
--- a/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/api/FakeApi.java
+++ b/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/api/FakeApi.java
@@ -152,8 +152,8 @@ public interface FakeApi {
         @ApiResponse(code = 400, message = "Someting wrong") })
     @RequestMapping(value = "/fake",
         method = RequestMethod.DELETE)
-    default Mono<ResponseEntity<Void>> testGroupParameters(@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group, ServerWebExchange exchange) {
-        return getDelegate().testGroupParameters(stringGroup, booleanGroup, int64Group, exchange);
+    default Mono<ResponseEntity<Void>> testGroupParameters(@NotNull @ApiParam(value = "Required String in group parameters", required = true) @Valid @RequestParam(value = "required_string_group", required = true) Integer requiredStringGroup,@ApiParam(value = "Required Boolean in group parameters" ,required=true) @RequestHeader(value="required_boolean_group", required=true) Boolean requiredBooleanGroup,@NotNull @ApiParam(value = "Required Integer in group parameters", required = true) @Valid @RequestParam(value = "required_int64_group", required = true) Long requiredInt64Group,@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group, ServerWebExchange exchange) {
+        return getDelegate().testGroupParameters(requiredStringGroup, requiredBooleanGroup, requiredInt64Group, stringGroup, booleanGroup, int64Group, exchange);
     }
 
 
diff --git a/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/api/FakeApiDelegate.java b/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/api/FakeApiDelegate.java
index 117a233a8e0..3b3f23ccece 100644
--- a/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/api/FakeApiDelegate.java
+++ b/samples/server/petstore/springboot-reactive/src/main/java/org/openapitools/api/FakeApiDelegate.java
@@ -170,7 +170,10 @@ public interface FakeApiDelegate {
     /**
      * @see FakeApi#testGroupParameters
      */
-    default Mono<ResponseEntity<Void>> testGroupParameters(Integer stringGroup,
+    default Mono<ResponseEntity<Void>> testGroupParameters(Integer requiredStringGroup,
+        Boolean requiredBooleanGroup,
+        Long requiredInt64Group,
+        Integer stringGroup,
         Boolean booleanGroup,
         Long int64Group,
         ServerWebExchange exchange) {
diff --git a/samples/server/petstore/springboot-reactive/src/main/resources/openapi.yaml b/samples/server/petstore/springboot-reactive/src/main/resources/openapi.yaml
index ad445e88402..f3f7ba18010 100644
--- a/samples/server/petstore/springboot-reactive/src/main/resources/openapi.yaml
+++ b/samples/server/petstore/springboot-reactive/src/main/resources/openapi.yaml
@@ -666,6 +666,25 @@ paths:
       description: Fake endpoint to test group parameters (optional)
       operationId: testGroupParameters
       parameters:
+      - description: Required String in group parameters
+        in: query
+        name: required_string_group
+        required: true
+        schema:
+          type: integer
+      - description: Required Boolean in group parameters
+        in: header
+        name: required_boolean_group
+        required: true
+        schema:
+          type: boolean
+      - description: Required Integer in group parameters
+        in: query
+        name: required_int64_group
+        required: true
+        schema:
+          format: int64
+          type: integer
       - description: String in group parameters
         in: query
         name: string_group
diff --git a/samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/api/FakeApi.java b/samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/api/FakeApi.java
index 4805c6d10a6..5885a85911f 100644
--- a/samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/api/FakeApi.java
+++ b/samples/server/petstore/springboot-useoptional/src/main/java/org/openapitools/api/FakeApi.java
@@ -178,7 +178,7 @@ public interface FakeApi {
         @ApiResponse(code = 400, message = "Someting wrong") })
     @RequestMapping(value = "/fake",
         method = RequestMethod.DELETE)
-    default ResponseEntity<Void> testGroupParameters(@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Optional<Integer> stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Optional<Boolean> booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Optional<Long> int64Group) {
+    default ResponseEntity<Void> testGroupParameters(@NotNull @ApiParam(value = "Required String in group parameters", required = true) @Valid @RequestParam(value = "required_string_group", required = true) Integer requiredStringGroup,@ApiParam(value = "Required Boolean in group parameters" ,required=true) @RequestHeader(value="required_boolean_group", required=true) Boolean requiredBooleanGroup,@NotNull @ApiParam(value = "Required Integer in group parameters", required = true) @Valid @RequestParam(value = "required_int64_group", required = true) Long requiredInt64Group,@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Optional<Integer> stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Optional<Boolean> booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Optional<Long> int64Group) {
         return new ResponseEntity<>(HttpStatus.NOT_IMPLEMENTED);
 
     }
diff --git a/samples/server/petstore/springboot-virtualan/src/main/java/org/openapitools/virtualan/api/FakeApi.java b/samples/server/petstore/springboot-virtualan/src/main/java/org/openapitools/virtualan/api/FakeApi.java
index e54182d3ae6..d6095b486e5 100644
--- a/samples/server/petstore/springboot-virtualan/src/main/java/org/openapitools/virtualan/api/FakeApi.java
+++ b/samples/server/petstore/springboot-virtualan/src/main/java/org/openapitools/virtualan/api/FakeApi.java
@@ -191,7 +191,7 @@ public interface FakeApi {
         @ApiResponse(code = 400, message = "Someting wrong") })
     @RequestMapping(value = "/fake",
         method = RequestMethod.DELETE)
-    default ResponseEntity<Void> testGroupParameters(@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group) {
+    default ResponseEntity<Void> testGroupParameters(@NotNull @ApiParam(value = "Required String in group parameters", required = true) @Valid @RequestParam(value = "required_string_group", required = true) Integer requiredStringGroup,@ApiParam(value = "Required Boolean in group parameters" ,required=true) @RequestHeader(value="required_boolean_group", required=true) Boolean requiredBooleanGroup,@NotNull @ApiParam(value = "Required Integer in group parameters", required = true) @Valid @RequestParam(value = "required_int64_group", required = true) Long requiredInt64Group,@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group) {
         return new ResponseEntity<>(HttpStatus.NOT_IMPLEMENTED);
 
     }
diff --git a/samples/server/petstore/springboot/src/main/java/org/openapitools/api/FakeApi.java b/samples/server/petstore/springboot/src/main/java/org/openapitools/api/FakeApi.java
index a3a21d4172b..5ec7e4c7052 100644
--- a/samples/server/petstore/springboot/src/main/java/org/openapitools/api/FakeApi.java
+++ b/samples/server/petstore/springboot/src/main/java/org/openapitools/api/FakeApi.java
@@ -178,7 +178,7 @@ public interface FakeApi {
         @ApiResponse(code = 400, message = "Someting wrong") })
     @RequestMapping(value = "/fake",
         method = RequestMethod.DELETE)
-    default ResponseEntity<Void> testGroupParameters(@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group) {
+    default ResponseEntity<Void> testGroupParameters(@NotNull @ApiParam(value = "Required String in group parameters", required = true) @Valid @RequestParam(value = "required_string_group", required = true) Integer requiredStringGroup,@ApiParam(value = "Required Boolean in group parameters" ,required=true) @RequestHeader(value="required_boolean_group", required=true) Boolean requiredBooleanGroup,@NotNull @ApiParam(value = "Required Integer in group parameters", required = true) @Valid @RequestParam(value = "required_int64_group", required = true) Long requiredInt64Group,@ApiParam(value = "String in group parameters") @Valid @RequestParam(value = "string_group", required = false) Integer stringGroup,@ApiParam(value = "Boolean in group parameters" ) @RequestHeader(value="boolean_group", required=false) Boolean booleanGroup,@ApiParam(value = "Integer in group parameters") @Valid @RequestParam(value = "int64_group", required = false) Long int64Group) {
         return new ResponseEntity<>(HttpStatus.NOT_IMPLEMENTED);
 
     }