diff --git a/bin/configs/java-jersey2-8.yaml b/bin/configs/java-jersey2-8.yaml
index c10332368de3..f968aac62307 100644
--- a/bin/configs/java-jersey2-8.yaml
+++ b/bin/configs/java-jersey2-8.yaml
@@ -2,6 +2,7 @@ generatorName: java
 outputDir: samples/openapi3/client/petstore/java/jersey2-java8
 library: jersey2
 inputSpec: modules/openapi-generator/src/test/resources/3_0/java/petstore-with-fake-endpoints-models-for-testing-with-http-signature.yaml
+templateDir: modules/openapi-generator/src/main/resources/Java
 additionalProperties:
   artifactId: petstore-openapi3-jersey2-java8
   hideGenerationTimestamp: true
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
index 50e35cf40d11..7e18a8a393cb 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
@@ -1486,20 +1486,20 @@ public DefaultCodegen() {
 
         // option to change how we process + set the data in the 'additionalProperties' keyword.
         CliOption disallowAdditionalPropertiesIfNotPresentOpt = CliOption.newBoolean(
-            CodegenConstants.DISALLOW_ADDITIONAL_PROPERTIES_IF_NOT_PRESENT,
-            CodegenConstants.DISALLOW_ADDITIONAL_PROPERTIES_IF_NOT_PRESENT_DESC).defaultValue(Boolean.TRUE.toString());
+                CodegenConstants.DISALLOW_ADDITIONAL_PROPERTIES_IF_NOT_PRESENT,
+                CodegenConstants.DISALLOW_ADDITIONAL_PROPERTIES_IF_NOT_PRESENT_DESC).defaultValue(Boolean.TRUE.toString());
         Map<String, String> disallowAdditionalPropertiesIfNotPresentOpts = new HashMap<>();
         disallowAdditionalPropertiesIfNotPresentOpts.put("false",
-            "The 'additionalProperties' implementation is compliant with the OAS and JSON schema specifications.");
+                "The 'additionalProperties' implementation is compliant with the OAS and JSON schema specifications.");
         disallowAdditionalPropertiesIfNotPresentOpts.put("true",
-            "when the 'additionalProperties' keyword is not present in a schema, " +
-            "the value of 'additionalProperties' is automatically set to false, i.e. no additional properties are allowed. " +
-            "Note: this mode is not compliant with the JSON schema specification. " +
-            "This is the original openapi-generator behavior.");
+                "when the 'additionalProperties' keyword is not present in a schema, " +
+                "the value of 'additionalProperties' is automatically set to false, i.e. no additional properties are allowed. " +
+                "Note: this mode is not compliant with the JSON schema specification. " +
+                "This is the original openapi-generator behavior.");
         disallowAdditionalPropertiesIfNotPresentOpt.setEnum(disallowAdditionalPropertiesIfNotPresentOpts);
         cliOptions.add(disallowAdditionalPropertiesIfNotPresentOpt);
         this.setDisallowAdditionalPropertiesIfNotPresent(true);
-        
+
         // initialize special character mapping
         initalizeSpecialCharacterMapping();
 
@@ -2640,7 +2640,7 @@ private Discriminator recursiveGetDiscriminator(Schema sc, OpenAPI openAPI) {
                 Integer hasDiscriminatorCnt = 0;
                 Integer hasNullTypeCnt = 0;
                 Set<String> discriminatorsPropNames = new HashSet<>();
-                for  (Schema oneOf: composedSchema.getOneOf()) {
+                for (Schema oneOf : composedSchema.getOneOf()) {
                     if (ModelUtils.isNullType(oneOf)) {
                         // The null type does not have a discriminator. Skip.
                         hasNullTypeCnt++;
@@ -2654,7 +2654,7 @@ private Discriminator recursiveGetDiscriminator(Schema sc, OpenAPI openAPI) {
                 }
                 if (discriminatorsPropNames.size() > 1) {
                     throw new RuntimeException("The oneOf schemas have conflicting discriminator property names. " +
-                        "oneOf schemas must have the same property name, but found " + String.join(", ", discriminatorsPropNames));
+                            "oneOf schemas must have the same property name, but found " + String.join(", ", discriminatorsPropNames));
                 }
                 if ((hasDiscriminatorCnt + hasNullTypeCnt) == composedSchema.getOneOf().size() && discriminatorsPropNames.size() == 1) {
                     disc.setPropertyName(foundDisc.getPropertyName());
@@ -2669,7 +2669,7 @@ private Discriminator recursiveGetDiscriminator(Schema sc, OpenAPI openAPI) {
                 Integer hasDiscriminatorCnt = 0;
                 Integer hasNullTypeCnt = 0;
                 Set<String> discriminatorsPropNames = new HashSet<>();
-                for  (Schema anyOf: composedSchema.getAnyOf()) {
+                for  (Schema anyOf : composedSchema.getAnyOf()) {
                     if (ModelUtils.isNullType(anyOf)) {
                         // The null type does not have a discriminator. Skip.
                         hasNullTypeCnt++;
@@ -2720,7 +2720,7 @@ protected List<MappedModel> getOneOfAnyOfDescendants(String composedSchemaName,
             if (schemaList == null) {
                 continue;
             }
-            for  (Schema sc: schemaList) {
+            for (Schema sc : schemaList) {
                 if (ModelUtils.isNullType(sc)) {
                     continue;
                 }
@@ -2875,7 +2875,7 @@ protected CodegenDiscriminator createDiscriminator(String schemaName, Schema sch
      * Handle the model for the 'additionalProperties' keyword in the OAS schema.
      *
      * @param codegenModel The codegen representation of the schema.
-     * @param schema the input OAS schema.
+     * @param schema       The input OAS schema.
      */
     protected void addAdditionPropertiesToCodeGenModel(CodegenModel codegenModel, Schema schema) {
         addParentContainer(codegenModel, codegenModel.name, schema);
@@ -3503,7 +3503,7 @@ protected void handleMethodResponse(Operation operation,
             op.returnType = cm.dataType;
             op.returnFormat = cm.dataFormat;
             op.hasReference = schemas != null && schemas.containsKey(op.returnBaseType);
-             
+
             // lookup discriminator
             Schema schema = schemas.get(op.returnBaseType);
             if (schema != null) {
@@ -3965,8 +3965,8 @@ public CodegenResponse fromResponse(String responseCode, ApiResponse response) {
                 r.containerType = cp.containerType;
                 r.isMapContainer = "map".equals(cp.containerType);
                 r.isListContainer = "list".equalsIgnoreCase(cp.containerType) ||
-                    "array".equalsIgnoreCase(cp.containerType) ||
-                    "set".equalsIgnoreCase(cp.containerType);
+                        "array".equalsIgnoreCase(cp.containerType) ||
+                        "set".equalsIgnoreCase(cp.containerType);
             } else {
                 r.simpleType = true;
             }
@@ -4317,7 +4317,7 @@ public boolean isDataTypeBinary(String dataType) {
             return false;
         }
     }
-    
+
     // TODO revise below as it should be replaced by ModelUtils.isFileSchema(parameterSchema)
     public boolean isDataTypeFile(String dataType) {
         if (dataType != null) {
@@ -5795,6 +5795,7 @@ private void addBodyModelSchema(CodegenParameter codegenParameter, String name,
             codegenParameter.baseType = codegenModel.classname;
             codegenParameter.dataType = getTypeDeclaration(codegenModel.classname);
             codegenParameter.description = codegenModel.description;
+            codegenParameter.isNullable = codegenModel.isNullable;
             imports.add(codegenParameter.baseType);
         } else {
             CodegenProperty codegenProperty = fromProperty("property", schema);
@@ -5808,6 +5809,7 @@ private void addBodyModelSchema(CodegenParameter codegenParameter, String name,
                 codegenParameter.baseType = codegenParameter.baseName;
                 codegenParameter.dataType = getTypeDeclaration(codegenModelName);
                 codegenParameter.description = codegenProperty.getDescription();
+                codegenParameter.isNullable = codegenProperty.isNullable;
             } else {
                 if (ModelUtils.isMapSchema(schema)) {// http body is map
                     LOGGER.error("Map should be supported. Please report to openapi-generator github repo about the issue.");
@@ -5916,6 +5918,7 @@ public CodegenParameter fromRequestBody(RequestBody body, Set<String> imports, S
                 codegenParameter.baseType = getSchemaType(inner);
                 codegenParameter.isContainer = Boolean.TRUE;
                 codegenParameter.isMapContainer = Boolean.TRUE;
+                codegenParameter.isNullable = codegenProperty.isNullable;
 
                 setParameterBooleanFlagWithCodegenProperty(codegenParameter, codegenProperty);
 
@@ -5958,6 +5961,7 @@ public CodegenParameter fromRequestBody(RequestBody body, Set<String> imports, S
                 codegenParameter.baseType = getSchemaType(inner);
                 codegenParameter.isContainer = Boolean.TRUE;
                 codegenParameter.isListContainer = Boolean.TRUE;
+                codegenParameter.isNullable = codegenProperty.isNullable;
 
                 setParameterBooleanFlagWithCodegenProperty(codegenParameter, codegenProperty);
                 // set nullable
@@ -5981,6 +5985,7 @@ public CodegenParameter fromRequestBody(RequestBody body, Set<String> imports, S
                 codegenParameter.baseType = codegenProperty.baseType;
                 codegenParameter.dataType = codegenProperty.dataType;
                 codegenParameter.description = codegenProperty.description;
+                codegenParameter.isNullable = codegenProperty.isNullable;
                 codegenParameter.paramName = toParamName(codegenParameter.baseName);
             }
             setParameterBooleanFlagWithCodegenProperty(codegenParameter, codegenProperty);
@@ -6010,6 +6015,7 @@ public CodegenParameter fromRequestBody(RequestBody body, Set<String> imports, S
                 codegenParameter.minLength = codegenProperty.minLength;
                 codegenParameter.maxLength = codegenProperty.maxLength;
                 codegenParameter.pattern = codegenProperty.pattern;
+                codegenParameter.isNullable = codegenProperty.isNullable;
 
                 if (codegenProperty.complexType != null) {
                     imports.add(codegenProperty.complexType);
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/ApiClient.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/ApiClient.mustache
index a14b0c16f772..9d726cc93dc2 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/ApiClient.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/ApiClient.mustache
@@ -839,7 +839,7 @@ public class ApiClient {
    * @return Entity
    * @throws ApiException API exception
    */
-  public Entity<?> serialize(Object obj, Map<String, Object> formParams, String contentType) throws ApiException {
+  public Entity<?> serialize(Object obj, Map<String, Object> formParams, String contentType, boolean isBodyNullable) throws ApiException {
     Entity<?> entity;
     if (contentType.startsWith("multipart/form-data")) {
       MultiPart multiPart = new MultiPart();
@@ -863,7 +863,11 @@ public class ApiClient {
       entity = Entity.entity(form, MediaType.APPLICATION_FORM_URLENCODED_TYPE);
     } else {
       // We let jersey handle the serialization
-      entity = Entity.entity(obj == null ? Entity.text("") : obj, contentType);
+      if (isBodyNullable) { // payload is nullable
+        entity = Entity.entity(obj == null ? Entity.text("null") : obj, contentType);
+      } else {
+        entity = Entity.entity(obj == null ? Entity.text("") : obj, contentType);
+      }
     }
     return entity;
   }
@@ -874,10 +878,11 @@ public class ApiClient {
    * @param obj Object
    * @param formParams Form parameters
    * @param contentType Context type
+   * @param isBodyNulalble True if the body is nullable
    * @return String
    * @throws ApiException API exception
    */
-  public String serializeToString(Object obj, Map<String, Object> formParams, String contentType) throws ApiException {
+  public String serializeToString(Object obj, Map<String, Object> formParams, String contentType, boolean isBodyNullable) throws ApiException {
     try {
       if (contentType.startsWith("multipart/form-data")) {
         throw new ApiException("multipart/form-data not yet supported for serializeToString (http signature authentication)");
@@ -893,7 +898,11 @@ public class ApiClient {
           return formString.substring(0, formString.length() - 1);
         }
       } else {
-        return json.getMapper().writeValueAsString(obj);
+        if (isBodyNullable) {
+          return obj == null ? "null" : json.getMapper().writeValueAsString(obj);
+        } else {
+          return json.getMapper().writeValueAsString(obj);
+        }
       }
     } catch (Exception ex) {
       throw new ApiException("Failed to perform serializeToString: " + ex.toString());
@@ -1007,6 +1016,7 @@ public class ApiClient {
    * @param contentType The request's Content-Type header
    * @param authNames The authentications to apply
    * @param returnType The return type into which to deserialize the response
+   * @param isBodyNullable True if the body is nullable
    * @return The response body in type of string
    * @throws ApiException API exception
    */
@@ -1022,7 +1032,8 @@ public class ApiClient {
       String accept,
       String contentType,
       String[] authNames,
-      GenericType<T> returnType)
+      GenericType<T> returnType,
+      boolean isBodyNullable)
       throws ApiException {
 
     // Not using `.target(targetURL).path(path)` below,
@@ -1069,7 +1080,7 @@ public class ApiClient {
       }
     }
 
-    Entity<?> entity = serialize(body, formParams, contentType);
+    Entity<?> entity = serialize(body, formParams, contentType, isBodyNullable);
 
     // put all headers in one place
     Map<String, String> allHeaderParams = new HashMap<>(defaultHeaderMap);
@@ -1081,7 +1092,7 @@ public class ApiClient {
         queryParams,
         allHeaderParams,
         cookieParams,
-        serializeToString(body, formParams, contentType),
+        serializeToString(body, formParams, contentType, isBodyNullable),
         method,
         target.getUri());
 
@@ -1170,8 +1181,8 @@ public class ApiClient {
    * @deprecated Add qualified name of the operation as a first parameter.
    */
   @Deprecated
-  public <T> ApiResponse<T> invokeAPI(String path, String method, List<Pair> queryParams, Object body, Map<String, String> headerParams, Map<String, String> cookieParams, Map<String, Object> formParams, String accept, String contentType, String[] authNames, GenericType<T> returnType) throws ApiException {
-    return invokeAPI(null, path, method, queryParams, body, headerParams, cookieParams, formParams, accept, contentType, authNames, returnType);
+  public <T> ApiResponse<T> invokeAPI(String path, String method, List<Pair> queryParams, Object body, Map<String, String> headerParams, Map<String, String> cookieParams, Map<String, Object> formParams, String accept, String contentType, String[] authNames, GenericType<T> returnType, boolean isBodyNullable) throws ApiException {
+    return invokeAPI(null, path, method, queryParams, body, headerParams, cookieParams, formParams, accept, contentType, authNames, returnType, isBodyNullable);
   }
 
   /**
diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/api.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/api.mustache
index 16f7ef45b8c0..5fcfb9b19bb3 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/api.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/api.mustache
@@ -167,7 +167,7 @@ public class {{classname}} {
     {{/returnType}}
     return apiClient.invokeAPI("{{classname}}.{{operationId}}", localVarPath, "{{httpMethod}}", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, {{#returnType}}localVarReturnType{{/returnType}}{{^returnType}}null{{/returnType}});
+                               localVarAuthNames, {{#returnType}}localVarReturnType{{/returnType}}{{^returnType}}null{{/returnType}}, {{#bodyParam}}{{#isNullable}}true{{/isNullable}}{{^isNullable}}false{{/isNullable}}{{/bodyParam}}{{^bodyParam}}false{{/bodyParam}});
   }
   {{#vendorExtensions.x-group-parameters}}
 
diff --git a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/ApiClient.java b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/ApiClient.java
index b4d1f44d9d67..b619597d990c 100644
--- a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/ApiClient.java
@@ -756,7 +756,7 @@ public String escapeString(String str) {
    * @return Entity
    * @throws ApiException API exception
    */
-  public Entity<?> serialize(Object obj, Map<String, Object> formParams, String contentType) throws ApiException {
+  public Entity<?> serialize(Object obj, Map<String, Object> formParams, String contentType, boolean isBodyNullable) throws ApiException {
     Entity<?> entity;
     if (contentType.startsWith("multipart/form-data")) {
       MultiPart multiPart = new MultiPart();
@@ -780,7 +780,11 @@ public Entity<?> serialize(Object obj, Map<String, Object> formParams, String co
       entity = Entity.entity(form, MediaType.APPLICATION_FORM_URLENCODED_TYPE);
     } else {
       // We let jersey handle the serialization
-      entity = Entity.entity(obj == null ? Entity.text("") : obj, contentType);
+      if (isBodyNullable) { // payload is nullable
+        entity = Entity.entity(obj == null ? Entity.text("null") : obj, contentType);
+      } else {
+        entity = Entity.entity(obj == null ? Entity.text("") : obj, contentType);
+      }
     }
     return entity;
   }
@@ -791,10 +795,11 @@ public Entity<?> serialize(Object obj, Map<String, Object> formParams, String co
    * @param obj Object
    * @param formParams Form parameters
    * @param contentType Context type
+   * @param isBodyNulalble True if the body is nullable
    * @return String
    * @throws ApiException API exception
    */
-  public String serializeToString(Object obj, Map<String, Object> formParams, String contentType) throws ApiException {
+  public String serializeToString(Object obj, Map<String, Object> formParams, String contentType, boolean isBodyNullable) throws ApiException {
     try {
       if (contentType.startsWith("multipart/form-data")) {
         throw new ApiException("multipart/form-data not yet supported for serializeToString (http signature authentication)");
@@ -810,7 +815,11 @@ public String serializeToString(Object obj, Map<String, Object> formParams, Stri
           return formString.substring(0, formString.length() - 1);
         }
       } else {
-        return json.getMapper().writeValueAsString(obj);
+        if (isBodyNullable) {
+          return obj == null ? "null" : json.getMapper().writeValueAsString(obj);
+        } else {
+          return json.getMapper().writeValueAsString(obj);
+        }
       }
     } catch (Exception ex) {
       throw new ApiException("Failed to perform serializeToString: " + ex.toString());
@@ -918,6 +927,7 @@ public File prepareDownloadFile(Response response) throws IOException {
    * @param contentType The request's Content-Type header
    * @param authNames The authentications to apply
    * @param returnType The return type into which to deserialize the response
+   * @param isBodyNullable True if the body is nullable
    * @return The response body in type of string
    * @throws ApiException API exception
    */
@@ -933,7 +943,8 @@ public <T> ApiResponse<T> invokeAPI(
       String accept,
       String contentType,
       String[] authNames,
-      GenericType<T> returnType)
+      GenericType<T> returnType,
+      boolean isBodyNullable)
       throws ApiException {
 
     // Not using `.target(targetURL).path(path)` below,
@@ -980,7 +991,7 @@ public <T> ApiResponse<T> invokeAPI(
       }
     }
 
-    Entity<?> entity = serialize(body, formParams, contentType);
+    Entity<?> entity = serialize(body, formParams, contentType, isBodyNullable);
 
     // put all headers in one place
     Map<String, String> allHeaderParams = new HashMap<>(defaultHeaderMap);
@@ -992,7 +1003,7 @@ public <T> ApiResponse<T> invokeAPI(
         queryParams,
         allHeaderParams,
         cookieParams,
-        serializeToString(body, formParams, contentType),
+        serializeToString(body, formParams, contentType, isBodyNullable),
         method,
         target.getUri());
 
@@ -1079,8 +1090,8 @@ private Response sendRequest(String method, Invocation.Builder invocationBuilder
    * @deprecated Add qualified name of the operation as a first parameter.
    */
   @Deprecated
-  public <T> ApiResponse<T> invokeAPI(String path, String method, List<Pair> queryParams, Object body, Map<String, String> headerParams, Map<String, String> cookieParams, Map<String, Object> formParams, String accept, String contentType, String[] authNames, GenericType<T> returnType) throws ApiException {
-    return invokeAPI(null, path, method, queryParams, body, headerParams, cookieParams, formParams, accept, contentType, authNames, returnType);
+  public <T> ApiResponse<T> invokeAPI(String path, String method, List<Pair> queryParams, Object body, Map<String, String> headerParams, Map<String, String> cookieParams, Map<String, Object> formParams, String accept, String contentType, String[] authNames, GenericType<T> returnType, boolean isBodyNullable) throws ApiException {
+    return invokeAPI(null, path, method, queryParams, body, headerParams, cookieParams, formParams, accept, contentType, authNames, returnType, isBodyNullable);
   }
 
   /**
diff --git a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/AnotherFakeApi.java b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
index 71f267cfb539..00a2e3fcd4b4 100644
--- a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
+++ b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
@@ -110,6 +110,6 @@ public ApiResponse<Client> call123testSpecialTagsWithHttpInfo(Client body) throw
 
     return apiClient.invokeAPI("AnotherFakeApi.call123testSpecialTags", localVarPath, "PATCH", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
 }
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 d722d3f1a0fd..170ca91a961f 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
@@ -115,7 +115,7 @@ public ApiResponse<Void> createXmlItemWithHttpInfo(XmlItem xmlItem) throws ApiEx
 
     return apiClient.invokeAPI("FakeApi.createXmlItem", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * 
@@ -177,7 +177,7 @@ public ApiResponse<Boolean> fakeOuterBooleanSerializeWithHttpInfo(Boolean body)
 
     return apiClient.invokeAPI("FakeApi.fakeOuterBooleanSerialize", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * 
@@ -239,7 +239,7 @@ public ApiResponse<OuterComposite> fakeOuterCompositeSerializeWithHttpInfo(Outer
 
     return apiClient.invokeAPI("FakeApi.fakeOuterCompositeSerialize", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * 
@@ -301,7 +301,7 @@ public ApiResponse<BigDecimal> fakeOuterNumberSerializeWithHttpInfo(BigDecimal b
 
     return apiClient.invokeAPI("FakeApi.fakeOuterNumberSerialize", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * 
@@ -363,7 +363,7 @@ public ApiResponse<String> fakeOuterStringSerializeWithHttpInfo(String body) thr
 
     return apiClient.invokeAPI("FakeApi.fakeOuterStringSerialize", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * 
@@ -427,7 +427,7 @@ public ApiResponse<Void> testBodyWithFileSchemaWithHttpInfo(FileSchemaTestClass
 
     return apiClient.invokeAPI("FakeApi.testBodyWithFileSchema", localVarPath, "PUT", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * 
@@ -499,7 +499,7 @@ public ApiResponse<Void> testBodyWithQueryParamsWithHttpInfo(String query, User
 
     return apiClient.invokeAPI("FakeApi.testBodyWithQueryParams", localVarPath, "PUT", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * To test \&quot;client\&quot; model
@@ -566,7 +566,7 @@ public ApiResponse<Client> testClientModelWithHttpInfo(Client body) throws ApiEx
 
     return apiClient.invokeAPI("FakeApi.testClientModel", localVarPath, "PATCH", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * Fake endpoint for testing various parameters  假端點  偽のエンドポイント  가짜 엔드 포인트
@@ -701,7 +701,7 @@ public ApiResponse<Void> testEndpointParametersWithHttpInfo(BigDecimal number, D
 
     return apiClient.invokeAPI("FakeApi.testEndpointParameters", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * To test enum parameters
@@ -788,7 +788,7 @@ public ApiResponse<Void> testEnumParametersWithHttpInfo(List<String> enumHeaderS
 
     return apiClient.invokeAPI("FakeApi.testEnumParameters", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
 
 private ApiResponse<Void> testGroupParametersWithHttpInfo(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
@@ -844,7 +844,7 @@ private ApiResponse<Void> testGroupParametersWithHttpInfo(Integer requiredString
 
     return apiClient.invokeAPI("FakeApi.testGroupParameters", localVarPath, "DELETE", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
 
   public class APItestGroupParametersRequest {
@@ -1023,7 +1023,7 @@ public ApiResponse<Void> testInlineAdditionalPropertiesWithHttpInfo(Map<String,
 
     return apiClient.invokeAPI("FakeApi.testInlineAdditionalProperties", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * test json serialization of form data
@@ -1098,7 +1098,7 @@ public ApiResponse<Void> testJsonFormDataWithHttpInfo(String param, String param
 
     return apiClient.invokeAPI("FakeApi.testJsonFormData", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * 
@@ -1195,6 +1195,6 @@ public ApiResponse<Void> testQueryParameterCollectionFormatWithHttpInfo(List<Str
 
     return apiClient.invokeAPI("FakeApi.testQueryParameterCollectionFormat", localVarPath, "PUT", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
 }
diff --git a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
index 602c6f69391b..1694d007f192 100644
--- a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
+++ b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
@@ -110,6 +110,6 @@ public ApiResponse<Client> testClassnameWithHttpInfo(Client body) throws ApiExce
 
     return apiClient.invokeAPI("FakeClassnameTags123Api.testClassname", localVarPath, "PATCH", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
 }
diff --git a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/PetApi.java b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/PetApi.java
index 601ccd197048..71fe54b109ea 100644
--- a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/PetApi.java
+++ b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/PetApi.java
@@ -112,7 +112,7 @@ public ApiResponse<Void> addPetWithHttpInfo(Pet body) throws ApiException {
 
     return apiClient.invokeAPI("PetApi.addPet", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * Deletes a pet
@@ -183,7 +183,7 @@ public ApiResponse<Void> deletePetWithHttpInfo(Long petId, String apiKey) throws
 
     return apiClient.invokeAPI("PetApi.deletePet", localVarPath, "DELETE", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * Finds Pets by status
@@ -253,7 +253,7 @@ public ApiResponse<List<Pet>> findPetsByStatusWithHttpInfo(List<String> status)
 
     return apiClient.invokeAPI("PetApi.findPetsByStatus", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * Finds Pets by tags
@@ -327,7 +327,7 @@ public ApiResponse<Set<Pet>> findPetsByTagsWithHttpInfo(Set<String> tags) throws
 
     return apiClient.invokeAPI("PetApi.findPetsByTags", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * Find pet by ID
@@ -399,7 +399,7 @@ public ApiResponse<Pet> getPetByIdWithHttpInfo(Long petId) throws ApiException {
 
     return apiClient.invokeAPI("PetApi.getPetById", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * Update an existing pet
@@ -469,7 +469,7 @@ public ApiResponse<Void> updatePetWithHttpInfo(Pet body) throws ApiException {
 
     return apiClient.invokeAPI("PetApi.updatePet", localVarPath, "PUT", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * Updates a pet in the store with form data
@@ -542,7 +542,7 @@ public ApiResponse<Void> updatePetWithFormWithHttpInfo(Long petId, String name,
 
     return apiClient.invokeAPI("PetApi.updatePetWithForm", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * uploads an image
@@ -618,7 +618,7 @@ public ApiResponse<ModelApiResponse> uploadFileWithHttpInfo(Long petId, String a
 
     return apiClient.invokeAPI("PetApi.uploadFile", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * uploads an image (required)
@@ -699,6 +699,6 @@ public ApiResponse<ModelApiResponse> uploadFileWithRequiredFileWithHttpInfo(Long
 
     return apiClient.invokeAPI("PetApi.uploadFileWithRequiredFile", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
 }
diff --git a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/StoreApi.java b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/StoreApi.java
index 31f441e5e1ba..0d259914167b 100644
--- a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/StoreApi.java
+++ b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/StoreApi.java
@@ -110,7 +110,7 @@ public ApiResponse<Void> deleteOrderWithHttpInfo(String orderId) throws ApiExcep
 
     return apiClient.invokeAPI("StoreApi.deleteOrder", localVarPath, "DELETE", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * Returns pet inventories by status
@@ -170,7 +170,7 @@ public ApiResponse<Map<String, Integer>> getInventoryWithHttpInfo() throws ApiEx
 
     return apiClient.invokeAPI("StoreApi.getInventory", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * Find purchase order by ID
@@ -242,7 +242,7 @@ public ApiResponse<Order> getOrderByIdWithHttpInfo(Long orderId) throws ApiExcep
 
     return apiClient.invokeAPI("StoreApi.getOrderById", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * Place an order for a pet
@@ -311,6 +311,6 @@ public ApiResponse<Order> placeOrderWithHttpInfo(Order body) throws ApiException
 
     return apiClient.invokeAPI("StoreApi.placeOrder", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
 }
diff --git a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/UserApi.java b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/UserApi.java
index 5dc1dd791c39..cf1f8c794073 100644
--- a/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/UserApi.java
+++ b/samples/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/UserApi.java
@@ -107,7 +107,7 @@ public ApiResponse<Void> createUserWithHttpInfo(User body) throws ApiException {
 
     return apiClient.invokeAPI("UserApi.createUser", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * Creates list of users with given input array
@@ -171,7 +171,7 @@ public ApiResponse<Void> createUsersWithArrayInputWithHttpInfo(List<User> body)
 
     return apiClient.invokeAPI("UserApi.createUsersWithArrayInput", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * Creates list of users with given input array
@@ -235,7 +235,7 @@ public ApiResponse<Void> createUsersWithListInputWithHttpInfo(List<User> body) t
 
     return apiClient.invokeAPI("UserApi.createUsersWithListInput", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * Delete user
@@ -302,7 +302,7 @@ public ApiResponse<Void> deleteUserWithHttpInfo(String username) throws ApiExcep
 
     return apiClient.invokeAPI("UserApi.deleteUser", localVarPath, "DELETE", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * Get user by user name
@@ -374,7 +374,7 @@ public ApiResponse<User> getUserByNameWithHttpInfo(String username) throws ApiEx
 
     return apiClient.invokeAPI("UserApi.getUserByName", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * Logs user into the system
@@ -452,7 +452,7 @@ public ApiResponse<String> loginUserWithHttpInfo(String username, String passwor
 
     return apiClient.invokeAPI("UserApi.loginUser", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * Logs out current logged in user session
@@ -509,7 +509,7 @@ public ApiResponse<Void> logoutUserWithHttpInfo() throws ApiException {
 
     return apiClient.invokeAPI("UserApi.logoutUser", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * Updated user
@@ -583,6 +583,6 @@ public ApiResponse<Void> updateUserWithHttpInfo(String username, User body) thro
 
     return apiClient.invokeAPI("UserApi.updateUser", localVarPath, "PUT", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
 }
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/ApiClient.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/ApiClient.java
index 63dbd385df52..2afd13332401 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/ApiClient.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/ApiClient.java
@@ -835,7 +835,7 @@ public String escapeString(String str) {
    * @return Entity
    * @throws ApiException API exception
    */
-  public Entity<?> serialize(Object obj, Map<String, Object> formParams, String contentType) throws ApiException {
+  public Entity<?> serialize(Object obj, Map<String, Object> formParams, String contentType, boolean isBodyNullable) throws ApiException {
     Entity<?> entity;
     if (contentType.startsWith("multipart/form-data")) {
       MultiPart multiPart = new MultiPart();
@@ -859,7 +859,11 @@ public Entity<?> serialize(Object obj, Map<String, Object> formParams, String co
       entity = Entity.entity(form, MediaType.APPLICATION_FORM_URLENCODED_TYPE);
     } else {
       // We let jersey handle the serialization
-      entity = Entity.entity(obj == null ? Entity.text("") : obj, contentType);
+      if (isBodyNullable) { // payload is nullable
+        entity = Entity.entity(obj == null ? Entity.text("null") : obj, contentType);
+      } else {
+        entity = Entity.entity(obj == null ? Entity.text("") : obj, contentType);
+      }
     }
     return entity;
   }
@@ -870,10 +874,11 @@ public Entity<?> serialize(Object obj, Map<String, Object> formParams, String co
    * @param obj Object
    * @param formParams Form parameters
    * @param contentType Context type
+   * @param isBodyNulalble True if the body is nullable
    * @return String
    * @throws ApiException API exception
    */
-  public String serializeToString(Object obj, Map<String, Object> formParams, String contentType) throws ApiException {
+  public String serializeToString(Object obj, Map<String, Object> formParams, String contentType, boolean isBodyNullable) throws ApiException {
     try {
       if (contentType.startsWith("multipart/form-data")) {
         throw new ApiException("multipart/form-data not yet supported for serializeToString (http signature authentication)");
@@ -889,7 +894,11 @@ public String serializeToString(Object obj, Map<String, Object> formParams, Stri
           return formString.substring(0, formString.length() - 1);
         }
       } else {
-        return json.getMapper().writeValueAsString(obj);
+        if (isBodyNullable) {
+          return obj == null ? "null" : json.getMapper().writeValueAsString(obj);
+        } else {
+          return json.getMapper().writeValueAsString(obj);
+        }
       }
     } catch (Exception ex) {
       throw new ApiException("Failed to perform serializeToString: " + ex.toString());
@@ -997,6 +1006,7 @@ public File prepareDownloadFile(Response response) throws IOException {
    * @param contentType The request's Content-Type header
    * @param authNames The authentications to apply
    * @param returnType The return type into which to deserialize the response
+   * @param isBodyNullable True if the body is nullable
    * @return The response body in type of string
    * @throws ApiException API exception
    */
@@ -1012,7 +1022,8 @@ public <T> ApiResponse<T> invokeAPI(
       String accept,
       String contentType,
       String[] authNames,
-      GenericType<T> returnType)
+      GenericType<T> returnType,
+      boolean isBodyNullable)
       throws ApiException {
 
     // Not using `.target(targetURL).path(path)` below,
@@ -1059,7 +1070,7 @@ public <T> ApiResponse<T> invokeAPI(
       }
     }
 
-    Entity<?> entity = serialize(body, formParams, contentType);
+    Entity<?> entity = serialize(body, formParams, contentType, isBodyNullable);
 
     // put all headers in one place
     Map<String, String> allHeaderParams = new HashMap<>(defaultHeaderMap);
@@ -1071,7 +1082,7 @@ public <T> ApiResponse<T> invokeAPI(
         queryParams,
         allHeaderParams,
         cookieParams,
-        serializeToString(body, formParams, contentType),
+        serializeToString(body, formParams, contentType, isBodyNullable),
         method,
         target.getUri());
 
@@ -1158,8 +1169,8 @@ private Response sendRequest(String method, Invocation.Builder invocationBuilder
    * @deprecated Add qualified name of the operation as a first parameter.
    */
   @Deprecated
-  public <T> ApiResponse<T> invokeAPI(String path, String method, List<Pair> queryParams, Object body, Map<String, String> headerParams, Map<String, String> cookieParams, Map<String, Object> formParams, String accept, String contentType, String[] authNames, GenericType<T> returnType) throws ApiException {
-    return invokeAPI(null, path, method, queryParams, body, headerParams, cookieParams, formParams, accept, contentType, authNames, returnType);
+  public <T> ApiResponse<T> invokeAPI(String path, String method, List<Pair> queryParams, Object body, Map<String, String> headerParams, Map<String, String> cookieParams, Map<String, Object> formParams, String accept, String contentType, String[] authNames, GenericType<T> returnType, boolean isBodyNullable) throws ApiException {
+    return invokeAPI(null, path, method, queryParams, body, headerParams, cookieParams, formParams, accept, contentType, authNames, returnType, isBodyNullable);
   }
 
   /**
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/AnotherFakeApi.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
index 2f2160899f82..7a9f7b08b63e 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
@@ -110,6 +110,6 @@ public ApiResponse<Client> call123testSpecialTagsWithHttpInfo(Client client) thr
 
     return apiClient.invokeAPI("AnotherFakeApi.call123testSpecialTags", localVarPath, "PATCH", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
 }
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/DefaultApi.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/DefaultApi.java
index 4444a7191f88..a49fdc11d859 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/DefaultApi.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/DefaultApi.java
@@ -103,6 +103,6 @@ public ApiResponse<InlineResponseDefault> fooGetWithHttpInfo() throws ApiExcepti
 
     return apiClient.invokeAPI("DefaultApi.fooGet", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
 }
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/FakeApi.java
index dacb046a1dfc..b8893ee704f7 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -112,7 +112,7 @@ public ApiResponse<HealthCheckResult> fakeHealthGetWithHttpInfo() throws ApiExce
 
     return apiClient.invokeAPI("FakeApi.fakeHealthGet", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * 
@@ -174,7 +174,7 @@ public ApiResponse<Boolean> fakeOuterBooleanSerializeWithHttpInfo(Boolean body)
 
     return apiClient.invokeAPI("FakeApi.fakeOuterBooleanSerialize", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * 
@@ -236,7 +236,7 @@ public ApiResponse<OuterComposite> fakeOuterCompositeSerializeWithHttpInfo(Outer
 
     return apiClient.invokeAPI("FakeApi.fakeOuterCompositeSerialize", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * 
@@ -298,7 +298,7 @@ public ApiResponse<BigDecimal> fakeOuterNumberSerializeWithHttpInfo(BigDecimal b
 
     return apiClient.invokeAPI("FakeApi.fakeOuterNumberSerialize", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * 
@@ -360,7 +360,7 @@ public ApiResponse<String> fakeOuterStringSerializeWithHttpInfo(String body) thr
 
     return apiClient.invokeAPI("FakeApi.fakeOuterStringSerialize", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * Array of Enums
@@ -420,7 +420,7 @@ public ApiResponse<List<OuterEnum>> getArrayOfEnumsWithHttpInfo() throws ApiExce
 
     return apiClient.invokeAPI("FakeApi.getArrayOfEnums", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * 
@@ -484,7 +484,7 @@ public ApiResponse<Void> testBodyWithFileSchemaWithHttpInfo(FileSchemaTestClass
 
     return apiClient.invokeAPI("FakeApi.testBodyWithFileSchema", localVarPath, "PUT", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * 
@@ -556,7 +556,7 @@ public ApiResponse<Void> testBodyWithQueryParamsWithHttpInfo(String query, User
 
     return apiClient.invokeAPI("FakeApi.testBodyWithQueryParams", localVarPath, "PUT", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * To test \&quot;client\&quot; model
@@ -623,7 +623,7 @@ public ApiResponse<Client> testClientModelWithHttpInfo(Client client) throws Api
 
     return apiClient.invokeAPI("FakeApi.testClientModel", localVarPath, "PATCH", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * Fake endpoint for testing various parameters 假端點 偽のエンドポイント 가짜 엔드 포인트 
@@ -758,7 +758,7 @@ public ApiResponse<Void> testEndpointParametersWithHttpInfo(BigDecimal number, D
 
     return apiClient.invokeAPI("FakeApi.testEndpointParameters", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * To test enum parameters
@@ -845,7 +845,7 @@ public ApiResponse<Void> testEnumParametersWithHttpInfo(List<String> enumHeaderS
 
     return apiClient.invokeAPI("FakeApi.testEnumParameters", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
 
 private ApiResponse<Void> testGroupParametersWithHttpInfo(Integer requiredStringGroup, Boolean requiredBooleanGroup, Long requiredInt64Group, Integer stringGroup, Boolean booleanGroup, Long int64Group) throws ApiException {
@@ -901,7 +901,7 @@ private ApiResponse<Void> testGroupParametersWithHttpInfo(Integer requiredString
 
     return apiClient.invokeAPI("FakeApi.testGroupParameters", localVarPath, "DELETE", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
 
   public class APItestGroupParametersRequest {
@@ -1080,7 +1080,7 @@ public ApiResponse<Void> testInlineAdditionalPropertiesWithHttpInfo(Map<String,
 
     return apiClient.invokeAPI("FakeApi.testInlineAdditionalProperties", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * test json serialization of form data
@@ -1155,7 +1155,7 @@ public ApiResponse<Void> testJsonFormDataWithHttpInfo(String param, String param
 
     return apiClient.invokeAPI("FakeApi.testJsonFormData", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * 
@@ -1252,6 +1252,6 @@ public ApiResponse<Void> testQueryParameterCollectionFormatWithHttpInfo(List<Str
 
     return apiClient.invokeAPI("FakeApi.testQueryParameterCollectionFormat", localVarPath, "PUT", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
 }
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
index f6b87e214fbb..fe39623440e6 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
@@ -110,6 +110,6 @@ public ApiResponse<Client> testClassnameWithHttpInfo(Client client) throws ApiEx
 
     return apiClient.invokeAPI("FakeClassnameTags123Api.testClassname", localVarPath, "PATCH", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
 }
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/PetApi.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/PetApi.java
index 6cd72b9701ea..3637b9e61a5a 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/PetApi.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/PetApi.java
@@ -109,7 +109,7 @@ public ApiResponse<Void> addPetWithHttpInfo(Pet pet) throws ApiException {
 
     return apiClient.invokeAPI("PetApi.addPet", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * Deletes a pet
@@ -178,7 +178,7 @@ public ApiResponse<Void> deletePetWithHttpInfo(Long petId, String apiKey) throws
 
     return apiClient.invokeAPI("PetApi.deletePet", localVarPath, "DELETE", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * Finds Pets by status
@@ -248,7 +248,7 @@ public ApiResponse<List<Pet>> findPetsByStatusWithHttpInfo(List<String> status)
 
     return apiClient.invokeAPI("PetApi.findPetsByStatus", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * Finds Pets by tags
@@ -322,7 +322,7 @@ public ApiResponse<List<Pet>> findPetsByTagsWithHttpInfo(List<String> tags) thro
 
     return apiClient.invokeAPI("PetApi.findPetsByTags", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * Find pet by ID
@@ -394,7 +394,7 @@ public ApiResponse<Pet> getPetByIdWithHttpInfo(Long petId) throws ApiException {
 
     return apiClient.invokeAPI("PetApi.getPetById", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * Update an existing pet
@@ -462,7 +462,7 @@ public ApiResponse<Void> updatePetWithHttpInfo(Pet pet) throws ApiException {
 
     return apiClient.invokeAPI("PetApi.updatePet", localVarPath, "PUT", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * Updates a pet in the store with form data
@@ -535,7 +535,7 @@ public ApiResponse<Void> updatePetWithFormWithHttpInfo(Long petId, String name,
 
     return apiClient.invokeAPI("PetApi.updatePetWithForm", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * uploads an image
@@ -611,7 +611,7 @@ public ApiResponse<ModelApiResponse> uploadFileWithHttpInfo(Long petId, String a
 
     return apiClient.invokeAPI("PetApi.uploadFile", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * uploads an image (required)
@@ -692,6 +692,6 @@ public ApiResponse<ModelApiResponse> uploadFileWithRequiredFileWithHttpInfo(Long
 
     return apiClient.invokeAPI("PetApi.uploadFileWithRequiredFile", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
 }
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/StoreApi.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/StoreApi.java
index eb4f5d3db86e..75fa95592c05 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/StoreApi.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/StoreApi.java
@@ -110,7 +110,7 @@ public ApiResponse<Void> deleteOrderWithHttpInfo(String orderId) throws ApiExcep
 
     return apiClient.invokeAPI("StoreApi.deleteOrder", localVarPath, "DELETE", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * Returns pet inventories by status
@@ -170,7 +170,7 @@ public ApiResponse<Map<String, Integer>> getInventoryWithHttpInfo() throws ApiEx
 
     return apiClient.invokeAPI("StoreApi.getInventory", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * Find purchase order by ID
@@ -242,7 +242,7 @@ public ApiResponse<Order> getOrderByIdWithHttpInfo(Long orderId) throws ApiExcep
 
     return apiClient.invokeAPI("StoreApi.getOrderById", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * Place an order for a pet
@@ -311,6 +311,6 @@ public ApiResponse<Order> placeOrderWithHttpInfo(Order order) throws ApiExceptio
 
     return apiClient.invokeAPI("StoreApi.placeOrder", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
 }
diff --git a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/UserApi.java b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/UserApi.java
index 0e0f07dca9fd..bdf2c62fcf0a 100644
--- a/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/UserApi.java
+++ b/samples/openapi3/client/petstore/java/jersey2-java8/src/main/java/org/openapitools/client/api/UserApi.java
@@ -107,7 +107,7 @@ public ApiResponse<Void> createUserWithHttpInfo(User user) throws ApiException {
 
     return apiClient.invokeAPI("UserApi.createUser", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * Creates list of users with given input array
@@ -171,7 +171,7 @@ public ApiResponse<Void> createUsersWithArrayInputWithHttpInfo(List<User> user)
 
     return apiClient.invokeAPI("UserApi.createUsersWithArrayInput", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * Creates list of users with given input array
@@ -235,7 +235,7 @@ public ApiResponse<Void> createUsersWithListInputWithHttpInfo(List<User> user) t
 
     return apiClient.invokeAPI("UserApi.createUsersWithListInput", localVarPath, "POST", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * Delete user
@@ -302,7 +302,7 @@ public ApiResponse<Void> deleteUserWithHttpInfo(String username) throws ApiExcep
 
     return apiClient.invokeAPI("UserApi.deleteUser", localVarPath, "DELETE", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * Get user by user name
@@ -374,7 +374,7 @@ public ApiResponse<User> getUserByNameWithHttpInfo(String username) throws ApiEx
 
     return apiClient.invokeAPI("UserApi.getUserByName", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * Logs user into the system
@@ -452,7 +452,7 @@ public ApiResponse<String> loginUserWithHttpInfo(String username, String passwor
 
     return apiClient.invokeAPI("UserApi.loginUser", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, localVarReturnType);
+                               localVarAuthNames, localVarReturnType, false);
   }
   /**
    * Logs out current logged in user session
@@ -509,7 +509,7 @@ public ApiResponse<Void> logoutUserWithHttpInfo() throws ApiException {
 
     return apiClient.invokeAPI("UserApi.logoutUser", localVarPath, "GET", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
   /**
    * Updated user
@@ -583,6 +583,6 @@ public ApiResponse<Void> updateUserWithHttpInfo(String username, User user) thro
 
     return apiClient.invokeAPI("UserApi.updateUser", localVarPath, "PUT", localVarQueryParams, localVarPostBody,
                                localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType,
-                               localVarAuthNames, null);
+                               localVarAuthNames, null, false);
   }
 }