diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/native/api.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/native/api.mustache
index 141d144b701..372ea771440 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/native/api.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/native/api.mustache
@@ -239,10 +239,9 @@ public class {{classname}} {
         }
         {{#vendorExtensions.x-java-text-plain-string}}
         // for plain text response
-        InputStream responseBody = localVarResponse.body();
         if (localVarResponse.headers().map().containsKey("Content-Type") &&
                 "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0))) {
-          java.util.Scanner s = new java.util.Scanner(responseBody).useDelimiter("\\A");
+          java.util.Scanner s = new java.util.Scanner(localVarResponse.body()).useDelimiter("\\A");
           String responseBodyText = s.hasNext() ? s.next() : "";
           return new ApiResponse<String>(
                   localVarResponse.statusCode(),
@@ -254,14 +253,11 @@ public class {{classname}} {
         }
         {{/vendorExtensions.x-java-text-plain-string}}
         {{^vendorExtensions.x-java-text-plain-string}}
-        {{#returnType}}
-        InputStream responseBody = localVarResponse.body();
-        {{/returnType}}
         return new ApiResponse<{{{returnType}}}{{^returnType}}Void{{/returnType}}>(
           localVarResponse.statusCode(),
           localVarResponse.headers().map(),
           {{#returnType}}
-          responseBody == null || responseBody.available() < 1 ? null : memberVarObjectMapper.readValue(responseBody, new TypeReference<{{{returnType}}}>() {}) // closes the InputStream
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<{{{returnType}}}>() {}) // closes the InputStream
           {{/returnType}}
           {{^returnType}}
           null
diff --git a/modules/openapi-generator/src/test/resources/3_0/echo_api.yaml b/modules/openapi-generator/src/test/resources/3_0/echo_api.yaml
index 34ef848a500..e04cd0b3575 100644
--- a/modules/openapi-generator/src/test/resources/3_0/echo_api.yaml
+++ b/modules/openapi-generator/src/test/resources/3_0/echo_api.yaml
@@ -26,6 +26,10 @@ info:
 servers:
   - url: http://localhost:3000/
 paths:
+  # Path usually starts with parameter type such as path, query, header, form
+  # For body/form parameters, path starts with "/echo" so the the echo server
+  # will response with the same body in the HTTP request.
+  #
   # path parameter tests
   /path/string/{path_string}/integer/{path_integer}:
     get:
@@ -133,8 +137,31 @@ paths:
             text/plain:
               schema:
                 type: string
+  /echo/body/Pet:
+    post:
+      tags:
+        - body
+      summary: Test body parameter(s)
+      description: Test body parameter(s)
+      operationId: test/echo/body/Pet
+      requestBody:
+        $ref: '#/components/requestBodies/Pet'
+      responses:
+        '200':
+          description: Successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Pet'
 
 components:
+  requestBodies:
+    Pet:
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/Pet'
+      description: Pet object that needs to be added to the store
   schemas:
     Category:
       type: object
diff --git a/samples/client/echo_api/java/apache-httpclient/.openapi-generator/FILES b/samples/client/echo_api/java/apache-httpclient/.openapi-generator/FILES
index c62abc624a1..c13a3b293ca 100644
--- a/samples/client/echo_api/java/apache-httpclient/.openapi-generator/FILES
+++ b/samples/client/echo_api/java/apache-httpclient/.openapi-generator/FILES
@@ -5,6 +5,7 @@ README.md
 api/openapi.yaml
 build.gradle
 build.sbt
+docs/BodyApi.md
 docs/Category.md
 docs/PathApi.md
 docs/Pet.md
@@ -29,6 +30,7 @@ src/main/java/org/openapitools/client/RFC3339DateFormat.java
 src/main/java/org/openapitools/client/ServerConfiguration.java
 src/main/java/org/openapitools/client/ServerVariable.java
 src/main/java/org/openapitools/client/StringUtil.java
+src/main/java/org/openapitools/client/api/BodyApi.java
 src/main/java/org/openapitools/client/api/PathApi.java
 src/main/java/org/openapitools/client/api/QueryApi.java
 src/main/java/org/openapitools/client/auth/ApiKeyAuth.java
diff --git a/samples/client/echo_api/java/apache-httpclient/README.md b/samples/client/echo_api/java/apache-httpclient/README.md
index 4b27be4f2bf..3f6adfee9d3 100644
--- a/samples/client/echo_api/java/apache-httpclient/README.md
+++ b/samples/client/echo_api/java/apache-httpclient/README.md
@@ -75,22 +75,21 @@ Please follow the [installation](#installation) instruction and execute the foll
 import org.openapitools.client.*;
 import org.openapitools.client.auth.*;
 import org.openapitools.client.model.*;
-import org.openapitools.client.api.PathApi;
+import org.openapitools.client.api.BodyApi;
 
-public class PathApiExample {
+public class BodyApiExample {
 
     public static void main(String[] args) {
         ApiClient defaultClient = Configuration.getDefaultApiClient();
         defaultClient.setBasePath("http://localhost:3000");
         
-        PathApi apiInstance = new PathApi(defaultClient);
-        String pathString = "pathString_example"; // String | 
-        Integer pathInteger = 56; // Integer | 
+        BodyApi apiInstance = new BodyApi(defaultClient);
+        Pet pet = new Pet(); // Pet | Pet object that needs to be added to the store
         try {
-            String result = apiInstance.testsPathStringPathStringIntegerPathInteger(pathString, pathInteger);
+            Pet result = apiInstance.testEchoBodyPet(pet);
             System.out.println(result);
         } catch (ApiException e) {
-            System.err.println("Exception when calling PathApi#testsPathStringPathStringIntegerPathInteger");
+            System.err.println("Exception when calling BodyApi#testEchoBodyPet");
             System.err.println("Status code: " + e.getCode());
             System.err.println("Reason: " + e.getResponseBody());
             System.err.println("Response headers: " + e.getResponseHeaders());
@@ -107,6 +106,7 @@ All URIs are relative to *http://localhost:3000*
 
 Class | Method | HTTP request | Description
 ------------ | ------------- | ------------- | -------------
+*BodyApi* | [**testEchoBodyPet**](docs/BodyApi.md#testEchoBodyPet) | **POST** /echo/body/Pet | Test body parameter(s)
 *PathApi* | [**testsPathStringPathStringIntegerPathInteger**](docs/PathApi.md#testsPathStringPathStringIntegerPathInteger) | **GET** /path/string/{path_string}/integer/{path_integer} | Test path parameter(s)
 *QueryApi* | [**testQueryIntegerBooleanString**](docs/QueryApi.md#testQueryIntegerBooleanString) | **GET** /query/integer/boolean/string | Test query parameter(s)
 *QueryApi* | [**testQueryStyleFormExplodeTrueArrayString**](docs/QueryApi.md#testQueryStyleFormExplodeTrueArrayString) | **GET** /query/style_form/explode_true/array_string | Test query parameter(s)
diff --git a/samples/client/echo_api/java/apache-httpclient/api/openapi.yaml b/samples/client/echo_api/java/apache-httpclient/api/openapi.yaml
index b782a803dab..4dd00e16318 100644
--- a/samples/client/echo_api/java/apache-httpclient/api/openapi.yaml
+++ b/samples/client/echo_api/java/apache-httpclient/api/openapi.yaml
@@ -124,9 +124,37 @@ paths:
       tags:
       - query
       x-accepts: text/plain
+  /echo/body/Pet:
+    post:
+      description: Test body parameter(s)
+      operationId: test/echo/body/Pet
+      requestBody:
+        $ref: '#/components/requestBodies/Pet'
+      responses:
+        "200":
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Pet'
+          description: Successful operation
+      summary: Test body parameter(s)
+      tags:
+      - body
+      x-content-type: application/json
+      x-accepts: application/json
 components:
+  requestBodies:
+    Pet:
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/Pet'
+      description: Pet object that needs to be added to the store
   schemas:
     Category:
+      example:
+        name: Dogs
+        id: 1
       properties:
         id:
           example: 1
@@ -139,6 +167,9 @@ components:
       xml:
         name: category
     Tag:
+      example:
+        name: name
+        id: 0
       properties:
         id:
           format: int64
@@ -149,6 +180,21 @@ components:
       xml:
         name: tag
     Pet:
+      example:
+        photoUrls:
+        - photoUrls
+        - photoUrls
+        name: doggie
+        id: 10
+        category:
+          name: Dogs
+          id: 1
+        tags:
+        - name: name
+          id: 0
+        - name: name
+          id: 0
+        status: available
       properties:
         id:
           example: 10
diff --git a/samples/client/echo_api/java/apache-httpclient/docs/BodyApi.md b/samples/client/echo_api/java/apache-httpclient/docs/BodyApi.md
new file mode 100644
index 00000000000..298dede6e49
--- /dev/null
+++ b/samples/client/echo_api/java/apache-httpclient/docs/BodyApi.md
@@ -0,0 +1,75 @@
+# BodyApi
+
+All URIs are relative to *http://localhost:3000*
+
+| Method | HTTP request | Description |
+|------------- | ------------- | -------------|
+| [**testEchoBodyPet**](BodyApi.md#testEchoBodyPet) | **POST** /echo/body/Pet | Test body parameter(s) |
+
+
+
+## testEchoBodyPet
+
+> Pet testEchoBodyPet(pet)
+
+Test body parameter(s)
+
+Test body parameter(s)
+
+### Example
+
+```java
+// Import classes:
+import org.openapitools.client.ApiClient;
+import org.openapitools.client.ApiException;
+import org.openapitools.client.Configuration;
+import org.openapitools.client.models.*;
+import org.openapitools.client.api.BodyApi;
+
+public class Example {
+    public static void main(String[] args) {
+        ApiClient defaultClient = Configuration.getDefaultApiClient();
+        defaultClient.setBasePath("http://localhost:3000");
+
+        BodyApi apiInstance = new BodyApi(defaultClient);
+        Pet pet = new Pet(); // Pet | Pet object that needs to be added to the store
+        try {
+            Pet result = apiInstance.testEchoBodyPet(pet);
+            System.out.println(result);
+        } catch (ApiException e) {
+            System.err.println("Exception when calling BodyApi#testEchoBodyPet");
+            System.err.println("Status code: " + e.getCode());
+            System.err.println("Reason: " + e.getResponseBody());
+            System.err.println("Response headers: " + e.getResponseHeaders());
+            e.printStackTrace();
+        }
+    }
+}
+```
+
+### Parameters
+
+
+| Name | Type | Description  | Notes |
+|------------- | ------------- | ------------- | -------------|
+| **pet** | [**Pet**](Pet.md)| Pet object that needs to be added to the store | [optional] |
+
+### Return type
+
+[**Pet**](Pet.md)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+- **Content-Type**: application/json
+- **Accept**: application/json
+
+
+### HTTP response details
+| Status code | Description | Response headers |
+|-------------|-------------|------------------|
+| **200** | Successful operation |  -  |
+
diff --git a/samples/client/echo_api/java/apache-httpclient/src/main/java/org/openapitools/client/api/BodyApi.java b/samples/client/echo_api/java/apache-httpclient/src/main/java/org/openapitools/client/api/BodyApi.java
new file mode 100644
index 00000000000..825922c1257
--- /dev/null
+++ b/samples/client/echo_api/java/apache-httpclient/src/main/java/org/openapitools/client/api/BodyApi.java
@@ -0,0 +1,102 @@
+/*
+ * Echo Server API
+ * Echo Server API
+ *
+ * The version of the OpenAPI document: 0.1.0
+ * Contact: team@openapitools.org
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package org.openapitools.client.api;
+
+import com.fasterxml.jackson.core.type.TypeReference;
+
+import org.openapitools.client.ApiException;
+import org.openapitools.client.ApiClient;
+import org.openapitools.client.Configuration;
+import org.openapitools.client.model.*;
+import org.openapitools.client.Pair;
+
+import org.openapitools.client.model.Pet;
+
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+@javax.annotation.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen")
+public class BodyApi {
+  private ApiClient apiClient;
+
+  public BodyApi() {
+    this(Configuration.getDefaultApiClient());
+  }
+
+  public BodyApi(ApiClient apiClient) {
+    this.apiClient = apiClient;
+  }
+
+  public ApiClient getApiClient() {
+    return apiClient;
+  }
+
+  public void setApiClient(ApiClient apiClient) {
+    this.apiClient = apiClient;
+  }
+
+  /**
+   * Test body parameter(s)
+   * Test body parameter(s)
+   * @param pet Pet object that needs to be added to the store (optional)
+   * @return Pet
+   * @throws ApiException if fails to make API call
+   */
+  public Pet testEchoBodyPet(Pet pet) throws ApiException {
+    Object localVarPostBody = pet;
+    
+    // create path and map variables
+    String localVarPath = "/echo/body/Pet";
+
+    // query params
+    List<Pair> localVarQueryParams = new ArrayList<Pair>();
+    List<Pair> localVarCollectionQueryParams = new ArrayList<Pair>();
+    Map<String, String> localVarHeaderParams = new HashMap<String, String>();
+    Map<String, String> localVarCookieParams = new HashMap<String, String>();
+    Map<String, Object> localVarFormParams = new HashMap<String, Object>();
+
+    
+    
+    
+    final String[] localVarAccepts = {
+      "application/json"
+    };
+    final String localVarAccept = apiClient.selectHeaderAccept(localVarAccepts);
+
+    final String[] localVarContentTypes = {
+      "application/json"
+    };
+    final String localVarContentType = apiClient.selectHeaderContentType(localVarContentTypes);
+
+    String[] localVarAuthNames = new String[] {  };
+
+    TypeReference<Pet> localVarReturnType = new TypeReference<Pet>() {};
+    return apiClient.invokeAPI(
+        localVarPath,
+        "POST",
+        localVarQueryParams,
+        localVarCollectionQueryParams,
+        localVarPostBody,
+        localVarHeaderParams,
+        localVarCookieParams,
+        localVarFormParams,
+        localVarAccept,
+        localVarContentType,
+        localVarAuthNames,
+        localVarReturnType
+    );
+  }
+}
diff --git a/samples/client/echo_api/java/apache-httpclient/src/test/java/org/openapitools/client/api/BodyApiTest.java b/samples/client/echo_api/java/apache-httpclient/src/test/java/org/openapitools/client/api/BodyApiTest.java
new file mode 100644
index 00000000000..352e8e2e19b
--- /dev/null
+++ b/samples/client/echo_api/java/apache-httpclient/src/test/java/org/openapitools/client/api/BodyApiTest.java
@@ -0,0 +1,52 @@
+/*
+ * Echo Server API
+ * Echo Server API
+ *
+ * The version of the OpenAPI document: 0.1.0
+ * Contact: team@openapitools.org
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.api;
+
+import org.openapitools.client.ApiException;
+import org.openapitools.client.model.Pet;
+import org.junit.Test;
+import org.junit.Ignore;
+import org.junit.Assert;
+
+import java.time.LocalDate;
+import java.time.OffsetDateTime;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * API tests for BodyApi
+ */
+@Ignore
+public class BodyApiTest {
+
+    private final BodyApi api = new BodyApi();
+
+    /**
+     * Test body parameter(s)
+     *
+     * Test body parameter(s)
+     *
+     * @throws ApiException
+     *          if the Api call fails
+     */
+    @Test
+    public void testEchoBodyPetTest() throws ApiException {
+        Pet pet = null;
+        Pet response = api.testEchoBodyPet(pet);
+
+        // TODO: test validations
+    }
+}
diff --git a/samples/client/echo_api/java/native/.openapi-generator/FILES b/samples/client/echo_api/java/native/.openapi-generator/FILES
index de036ed7e73..23dec04e62b 100644
--- a/samples/client/echo_api/java/native/.openapi-generator/FILES
+++ b/samples/client/echo_api/java/native/.openapi-generator/FILES
@@ -5,6 +5,7 @@ README.md
 api/openapi.yaml
 build.gradle
 build.sbt
+docs/BodyApi.md
 docs/Category.md
 docs/PathApi.md
 docs/Pet.md
@@ -29,6 +30,7 @@ src/main/java/org/openapitools/client/Pair.java
 src/main/java/org/openapitools/client/RFC3339DateFormat.java
 src/main/java/org/openapitools/client/ServerConfiguration.java
 src/main/java/org/openapitools/client/ServerVariable.java
+src/main/java/org/openapitools/client/api/BodyApi.java
 src/main/java/org/openapitools/client/api/PathApi.java
 src/main/java/org/openapitools/client/api/QueryApi.java
 src/main/java/org/openapitools/client/model/AbstractOpenApiSchema.java
diff --git a/samples/client/echo_api/java/native/README.md b/samples/client/echo_api/java/native/README.md
index b31d16de140..9a315449382 100644
--- a/samples/client/echo_api/java/native/README.md
+++ b/samples/client/echo_api/java/native/README.md
@@ -74,22 +74,21 @@ Please follow the [installation](#installation) instruction and execute the foll
 
 import org.openapitools.client.*;
 import org.openapitools.client.model.*;
-import org.openapitools.client.api.PathApi;
+import org.openapitools.client.api.BodyApi;
 
-public class PathApiExample {
+public class BodyApiExample {
 
     public static void main(String[] args) {
         ApiClient defaultClient = Configuration.getDefaultApiClient();
         // Configure clients using the `defaultClient` object, such as
         // overriding the host and port, timeout, etc.
-        PathApi apiInstance = new PathApi(defaultClient);
-        String pathString = "pathString_example"; // String | 
-        Integer pathInteger = 56; // Integer | 
+        BodyApi apiInstance = new BodyApi(defaultClient);
+        Pet pet = new Pet(); // Pet | Pet object that needs to be added to the store
         try {
-            String result = apiInstance.testsPathStringPathStringIntegerPathInteger(pathString, pathInteger);
+            Pet result = apiInstance.testEchoBodyPet(pet);
             System.out.println(result);
         } catch (ApiException e) {
-            System.err.println("Exception when calling PathApi#testsPathStringPathStringIntegerPathInteger");
+            System.err.println("Exception when calling BodyApi#testEchoBodyPet");
             System.err.println("Status code: " + e.getCode());
             System.err.println("Reason: " + e.getResponseBody());
             System.err.println("Response headers: " + e.getResponseHeaders());
@@ -106,6 +105,8 @@ All URIs are relative to *http://localhost:3000*
 
 Class | Method | HTTP request | Description
 ------------ | ------------- | ------------- | -------------
+*BodyApi* | [**testEchoBodyPet**](docs/BodyApi.md#testEchoBodyPet) | **POST** /echo/body/Pet | Test body parameter(s)
+*BodyApi* | [**testEchoBodyPetWithHttpInfo**](docs/BodyApi.md#testEchoBodyPetWithHttpInfo) | **POST** /echo/body/Pet | Test body parameter(s)
 *PathApi* | [**testsPathStringPathStringIntegerPathInteger**](docs/PathApi.md#testsPathStringPathStringIntegerPathInteger) | **GET** /path/string/{path_string}/integer/{path_integer} | Test path parameter(s)
 *PathApi* | [**testsPathStringPathStringIntegerPathIntegerWithHttpInfo**](docs/PathApi.md#testsPathStringPathStringIntegerPathIntegerWithHttpInfo) | **GET** /path/string/{path_string}/integer/{path_integer} | Test path parameter(s)
 *QueryApi* | [**testQueryIntegerBooleanString**](docs/QueryApi.md#testQueryIntegerBooleanString) | **GET** /query/integer/boolean/string | Test query parameter(s)
diff --git a/samples/client/echo_api/java/native/api/openapi.yaml b/samples/client/echo_api/java/native/api/openapi.yaml
index b782a803dab..4dd00e16318 100644
--- a/samples/client/echo_api/java/native/api/openapi.yaml
+++ b/samples/client/echo_api/java/native/api/openapi.yaml
@@ -124,9 +124,37 @@ paths:
       tags:
       - query
       x-accepts: text/plain
+  /echo/body/Pet:
+    post:
+      description: Test body parameter(s)
+      operationId: test/echo/body/Pet
+      requestBody:
+        $ref: '#/components/requestBodies/Pet'
+      responses:
+        "200":
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/Pet'
+          description: Successful operation
+      summary: Test body parameter(s)
+      tags:
+      - body
+      x-content-type: application/json
+      x-accepts: application/json
 components:
+  requestBodies:
+    Pet:
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/Pet'
+      description: Pet object that needs to be added to the store
   schemas:
     Category:
+      example:
+        name: Dogs
+        id: 1
       properties:
         id:
           example: 1
@@ -139,6 +167,9 @@ components:
       xml:
         name: category
     Tag:
+      example:
+        name: name
+        id: 0
       properties:
         id:
           format: int64
@@ -149,6 +180,21 @@ components:
       xml:
         name: tag
     Pet:
+      example:
+        photoUrls:
+        - photoUrls
+        - photoUrls
+        name: doggie
+        id: 10
+        category:
+          name: Dogs
+          id: 1
+        tags:
+        - name: name
+          id: 0
+        - name: name
+          id: 0
+        status: available
       properties:
         id:
           example: 10
diff --git a/samples/client/echo_api/java/native/docs/BodyApi.md b/samples/client/echo_api/java/native/docs/BodyApi.md
new file mode 100644
index 00000000000..f96e1e3d23d
--- /dev/null
+++ b/samples/client/echo_api/java/native/docs/BodyApi.md
@@ -0,0 +1,144 @@
+# BodyApi
+
+All URIs are relative to *http://localhost:3000*
+
+| Method | HTTP request | Description |
+|------------- | ------------- | -------------|
+| [**testEchoBodyPet**](BodyApi.md#testEchoBodyPet) | **POST** /echo/body/Pet | Test body parameter(s) |
+| [**testEchoBodyPetWithHttpInfo**](BodyApi.md#testEchoBodyPetWithHttpInfo) | **POST** /echo/body/Pet | Test body parameter(s) |
+
+
+
+## testEchoBodyPet
+
+> Pet testEchoBodyPet(pet)
+
+Test body parameter(s)
+
+Test body parameter(s)
+
+### Example
+
+```java
+// Import classes:
+import org.openapitools.client.ApiClient;
+import org.openapitools.client.ApiException;
+import org.openapitools.client.Configuration;
+import org.openapitools.client.models.*;
+import org.openapitools.client.api.BodyApi;
+
+public class Example {
+    public static void main(String[] args) {
+        ApiClient defaultClient = Configuration.getDefaultApiClient();
+        defaultClient.setBasePath("http://localhost:3000");
+
+        BodyApi apiInstance = new BodyApi(defaultClient);
+        Pet pet = new Pet(); // Pet | Pet object that needs to be added to the store
+        try {
+            Pet result = apiInstance.testEchoBodyPet(pet);
+            System.out.println(result);
+        } catch (ApiException e) {
+            System.err.println("Exception when calling BodyApi#testEchoBodyPet");
+            System.err.println("Status code: " + e.getCode());
+            System.err.println("Reason: " + e.getResponseBody());
+            System.err.println("Response headers: " + e.getResponseHeaders());
+            e.printStackTrace();
+        }
+    }
+}
+```
+
+### Parameters
+
+
+| Name | Type | Description  | Notes |
+|------------- | ------------- | ------------- | -------------|
+| **pet** | [**Pet**](Pet.md)| Pet object that needs to be added to the store | [optional] |
+
+### Return type
+
+[**Pet**](Pet.md)
+
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+- **Content-Type**: application/json
+- **Accept**: application/json
+
+### HTTP response details
+| Status code | Description | Response headers |
+|-------------|-------------|------------------|
+| **200** | Successful operation |  -  |
+
+## testEchoBodyPetWithHttpInfo
+
+> ApiResponse<Pet> testEchoBodyPet testEchoBodyPetWithHttpInfo(pet)
+
+Test body parameter(s)
+
+Test body parameter(s)
+
+### Example
+
+```java
+// Import classes:
+import org.openapitools.client.ApiClient;
+import org.openapitools.client.ApiException;
+import org.openapitools.client.ApiResponse;
+import org.openapitools.client.Configuration;
+import org.openapitools.client.models.*;
+import org.openapitools.client.api.BodyApi;
+
+public class Example {
+    public static void main(String[] args) {
+        ApiClient defaultClient = Configuration.getDefaultApiClient();
+        defaultClient.setBasePath("http://localhost:3000");
+
+        BodyApi apiInstance = new BodyApi(defaultClient);
+        Pet pet = new Pet(); // Pet | Pet object that needs to be added to the store
+        try {
+            ApiResponse<Pet> response = apiInstance.testEchoBodyPetWithHttpInfo(pet);
+            System.out.println("Status code: " + response.getStatusCode());
+            System.out.println("Response headers: " + response.getHeaders());
+            System.out.println("Response body: " + response.getData());
+        } catch (ApiException e) {
+            System.err.println("Exception when calling BodyApi#testEchoBodyPet");
+            System.err.println("Status code: " + e.getCode());
+            System.err.println("Response headers: " + e.getResponseHeaders());
+            System.err.println("Reason: " + e.getResponseBody());
+            e.printStackTrace();
+        }
+    }
+}
+```
+
+### Parameters
+
+
+| Name | Type | Description  | Notes |
+|------------- | ------------- | ------------- | -------------|
+| **pet** | [**Pet**](Pet.md)| Pet object that needs to be added to the store | [optional] |
+
+### Return type
+
+ApiResponse<[**Pet**](Pet.md)>
+
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+- **Content-Type**: application/json
+- **Accept**: application/json
+
+### HTTP response details
+| Status code | Description | Response headers |
+|-------------|-------------|------------------|
+| **200** | Successful operation |  -  |
+
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/BodyApi.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/BodyApi.java
new file mode 100644
index 00000000000..45c5b8e6e28
--- /dev/null
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/BodyApi.java
@@ -0,0 +1,150 @@
+/*
+ * Echo Server API
+ * Echo Server API
+ *
+ * The version of the OpenAPI document: 0.1.0
+ * Contact: team@openapitools.org
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package org.openapitools.client.api;
+
+import org.openapitools.client.ApiClient;
+import org.openapitools.client.ApiException;
+import org.openapitools.client.ApiResponse;
+import org.openapitools.client.Pair;
+
+import org.openapitools.client.model.Pet;
+
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.time.Duration;
+
+import java.util.ArrayList;
+import java.util.StringJoiner;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.function.Consumer;
+
+@javax.annotation.processing.Generated(value = "org.openapitools.codegen.languages.JavaClientCodegen")
+public class BodyApi {
+  private final HttpClient memberVarHttpClient;
+  private final ObjectMapper memberVarObjectMapper;
+  private final String memberVarBaseUri;
+  private final Consumer<HttpRequest.Builder> memberVarInterceptor;
+  private final Duration memberVarReadTimeout;
+  private final Consumer<HttpResponse<InputStream>> memberVarResponseInterceptor;
+  private final Consumer<HttpResponse<String>> memberVarAsyncResponseInterceptor;
+
+  public BodyApi() {
+    this(new ApiClient());
+  }
+
+  public BodyApi(ApiClient apiClient) {
+    memberVarHttpClient = apiClient.getHttpClient();
+    memberVarObjectMapper = apiClient.getObjectMapper();
+    memberVarBaseUri = apiClient.getBaseUri();
+    memberVarInterceptor = apiClient.getRequestInterceptor();
+    memberVarReadTimeout = apiClient.getReadTimeout();
+    memberVarResponseInterceptor = apiClient.getResponseInterceptor();
+    memberVarAsyncResponseInterceptor = apiClient.getAsyncResponseInterceptor();
+  }
+
+  protected ApiException getApiException(String operationId, HttpResponse<InputStream> response) throws IOException {
+    String body = response.body() == null ? null : new String(response.body().readAllBytes());
+    String message = formatExceptionMessage(operationId, response.statusCode(), body);
+    return new ApiException(response.statusCode(), message, response.headers(), body);
+  }
+
+  private String formatExceptionMessage(String operationId, int statusCode, String body) {
+    if (body == null || body.isEmpty()) {
+      body = "[no body]";
+    }
+    return operationId + " call failed with: " + statusCode + " - " + body;
+  }
+
+  /**
+   * Test body parameter(s)
+   * Test body parameter(s)
+   * @param pet Pet object that needs to be added to the store (optional)
+   * @return Pet
+   * @throws ApiException if fails to make API call
+   */
+  public Pet testEchoBodyPet(Pet pet) throws ApiException {
+    ApiResponse<Pet> localVarResponse = testEchoBodyPetWithHttpInfo(pet);
+    return localVarResponse.getData();
+  }
+
+  /**
+   * Test body parameter(s)
+   * Test body parameter(s)
+   * @param pet Pet object that needs to be added to the store (optional)
+   * @return ApiResponse&lt;Pet&gt;
+   * @throws ApiException if fails to make API call
+   */
+  public ApiResponse<Pet> testEchoBodyPetWithHttpInfo(Pet pet) throws ApiException {
+    HttpRequest.Builder localVarRequestBuilder = testEchoBodyPetRequestBuilder(pet);
+    try {
+      HttpResponse<InputStream> localVarResponse = memberVarHttpClient.send(
+          localVarRequestBuilder.build(),
+          HttpResponse.BodyHandlers.ofInputStream());
+      if (memberVarResponseInterceptor != null) {
+        memberVarResponseInterceptor.accept(localVarResponse);
+      }
+      try {
+        if (localVarResponse.statusCode()/ 100 != 2) {
+          throw getApiException("testEchoBodyPet", localVarResponse);
+        }
+        return new ApiResponse<Pet>(
+          localVarResponse.statusCode(),
+          localVarResponse.headers().map(),
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<Pet>() {}) // closes the InputStream
+        );
+      } finally {
+      }
+    } catch (IOException e) {
+      throw new ApiException(e);
+    }
+    catch (InterruptedException e) {
+      Thread.currentThread().interrupt();
+      throw new ApiException(e);
+    }
+  }
+
+  private HttpRequest.Builder testEchoBodyPetRequestBuilder(Pet pet) throws ApiException {
+
+    HttpRequest.Builder localVarRequestBuilder = HttpRequest.newBuilder();
+
+    String localVarPath = "/echo/body/Pet";
+
+    localVarRequestBuilder.uri(URI.create(memberVarBaseUri + localVarPath));
+
+    localVarRequestBuilder.header("Content-Type", "application/json");
+    localVarRequestBuilder.header("Accept", "application/json");
+
+    try {
+      byte[] localVarPostBody = memberVarObjectMapper.writeValueAsBytes(pet);
+      localVarRequestBuilder.method("POST", HttpRequest.BodyPublishers.ofByteArray(localVarPostBody));
+    } catch (IOException e) {
+      throw new ApiException(e);
+    }
+    if (memberVarReadTimeout != null) {
+      localVarRequestBuilder.timeout(memberVarReadTimeout);
+    }
+    if (memberVarInterceptor != null) {
+      memberVarInterceptor.accept(localVarRequestBuilder);
+    }
+    return localVarRequestBuilder;
+  }
+}
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/PathApi.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/PathApi.java
index dacf46dd260..911b0389b0f 100644
--- a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/PathApi.java
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/PathApi.java
@@ -108,10 +108,9 @@ public class PathApi {
           throw getApiException("testsPathStringPathStringIntegerPathInteger", localVarResponse);
         }
         // for plain text response
-        InputStream responseBody = localVarResponse.body();
         if (localVarResponse.headers().map().containsKey("Content-Type") &&
                 "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0))) {
-          java.util.Scanner s = new java.util.Scanner(responseBody).useDelimiter("\\A");
+          java.util.Scanner s = new java.util.Scanner(localVarResponse.body()).useDelimiter("\\A");
           String responseBodyText = s.hasNext() ? s.next() : "";
           return new ApiResponse<String>(
                   localVarResponse.statusCode(),
diff --git a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/QueryApi.java b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/QueryApi.java
index 406ee3b8fad..07add30bb3b 100644
--- a/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/QueryApi.java
+++ b/samples/client/echo_api/java/native/src/main/java/org/openapitools/client/api/QueryApi.java
@@ -112,10 +112,9 @@ public class QueryApi {
           throw getApiException("testQueryIntegerBooleanString", localVarResponse);
         }
         // for plain text response
-        InputStream responseBody = localVarResponse.body();
         if (localVarResponse.headers().map().containsKey("Content-Type") &&
                 "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0))) {
-          java.util.Scanner s = new java.util.Scanner(responseBody).useDelimiter("\\A");
+          java.util.Scanner s = new java.util.Scanner(localVarResponse.body()).useDelimiter("\\A");
           String responseBodyText = s.hasNext() ? s.next() : "";
           return new ApiResponse<String>(
                   localVarResponse.statusCode(),
@@ -199,10 +198,9 @@ public class QueryApi {
           throw getApiException("testQueryStyleFormExplodeTrueArrayString", localVarResponse);
         }
         // for plain text response
-        InputStream responseBody = localVarResponse.body();
         if (localVarResponse.headers().map().containsKey("Content-Type") &&
                 "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0))) {
-          java.util.Scanner s = new java.util.Scanner(responseBody).useDelimiter("\\A");
+          java.util.Scanner s = new java.util.Scanner(localVarResponse.body()).useDelimiter("\\A");
           String responseBodyText = s.hasNext() ? s.next() : "";
           return new ApiResponse<String>(
                   localVarResponse.statusCode(),
@@ -284,10 +282,9 @@ public class QueryApi {
           throw getApiException("testQueryStyleFormExplodeTrueObject", localVarResponse);
         }
         // for plain text response
-        InputStream responseBody = localVarResponse.body();
         if (localVarResponse.headers().map().containsKey("Content-Type") &&
                 "text/plain".equalsIgnoreCase(localVarResponse.headers().map().get("Content-Type").get(0))) {
-          java.util.Scanner s = new java.util.Scanner(responseBody).useDelimiter("\\A");
+          java.util.Scanner s = new java.util.Scanner(localVarResponse.body()).useDelimiter("\\A");
           String responseBodyText = s.hasNext() ? s.next() : "";
           return new ApiResponse<String>(
                   localVarResponse.statusCode(),
diff --git a/samples/client/echo_api/java/native/src/test/java/org/openapitools/client/CustomTest.java b/samples/client/echo_api/java/native/src/test/java/org/openapitools/client/CustomTest.java
index affbfae04a4..fb3e2cd4861 100644
--- a/samples/client/echo_api/java/native/src/test/java/org/openapitools/client/CustomTest.java
+++ b/samples/client/echo_api/java/native/src/test/java/org/openapitools/client/CustomTest.java
@@ -15,10 +15,8 @@ package org.openapitools.client;
 
 import org.junit.Assert;
 import org.openapitools.client.ApiException;
-import org.openapitools.client.api.QueryApi;
-import org.openapitools.client.model.Category;
-import org.openapitools.client.model.Pet;
-import org.openapitools.client.model.TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter;
+import org.openapitools.client.api.*;
+import org.openapitools.client.model.*;
 import org.junit.Test;
 import org.junit.Ignore;
 
@@ -31,8 +29,31 @@ import java.util.*;
 public class CustomTest {
 
     private final QueryApi api = new QueryApi();
+    private final BodyApi bodyApi = new BodyApi();
 
 
+    /**
+     * Test body parameter(s)
+     * <p>
+     * Test body parameter(s)
+     *
+     * @throws ApiException if the Api call fails
+     */
+    @Test
+    public void testEchoBodyPet() throws ApiException {
+        Pet queryObject = new Pet().id(12345L).name("Hello World").
+                photoUrls(Arrays.asList(new String[]{"http://a.com", "http://b.com"})).category(new Category().id(987L).name("new category"));
+
+        Pet p = bodyApi.testEchoBodyPet(queryObject);
+        Assert.assertNotNull(p);
+        Assert.assertEquals("Hello World", p.getName());
+        Assert.assertEquals(Long.valueOf(12345L), p.getId());
+
+        // response is empty body
+        Pet p2 = bodyApi.testEchoBodyPet(null);
+        Assert.assertNull(p2);
+    }
+
     /**
      * Test query parameter(s)
      * <p>
diff --git a/samples/client/echo_api/java/native/src/test/java/org/openapitools/client/api/BodyApiTest.java b/samples/client/echo_api/java/native/src/test/java/org/openapitools/client/api/BodyApiTest.java
new file mode 100644
index 00000000000..fc14326e06a
--- /dev/null
+++ b/samples/client/echo_api/java/native/src/test/java/org/openapitools/client/api/BodyApiTest.java
@@ -0,0 +1,54 @@
+/*
+ * Echo Server API
+ * Echo Server API
+ *
+ * The version of the OpenAPI document: 0.1.0
+ * Contact: team@openapitools.org
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.api;
+
+import org.openapitools.client.ApiException;
+import org.openapitools.client.model.Pet;
+import org.junit.Test;
+import org.junit.Ignore;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+
+/**
+ * API tests for BodyApi
+ */
+@Ignore
+public class BodyApiTest {
+
+    private final BodyApi api = new BodyApi();
+
+    
+    /**
+     * Test body parameter(s)
+     *
+     * Test body parameter(s)
+     *
+     * @throws ApiException
+     *          if the Api call fails
+     */
+    @Test
+    public void testEchoBodyPetTest() throws ApiException {
+        Pet pet = null;
+        Pet response = 
+        api.testEchoBodyPet(pet);
+        
+        // TODO: test validations
+    }
+    
+}
diff --git a/samples/client/others/typescript-axios/with-separate-models-and-api-inheritance/common.ts b/samples/client/others/typescript-axios/with-separate-models-and-api-inheritance/common.ts
index 6c84026abcc..cb72c04287d 100644
--- a/samples/client/others/typescript-axios/with-separate-models-and-api-inheritance/common.ts
+++ b/samples/client/others/typescript-axios/with-separate-models-and-api-inheritance/common.ts
@@ -85,6 +85,7 @@ export const setOAuthToObject = async function (object: any, name: string, scope
 }
 
 function setFlattenedQueryParams(urlSearchParams: URLSearchParams, parameter: any, key: string = ""): void {
+    if (parameter == null) return;
     if (typeof parameter === "object") {
         if (Array.isArray(parameter)) {
             (parameter as any[]).forEach(item => setFlattenedQueryParams(urlSearchParams, item, key));
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/AnotherFakeApi.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
index 3bff17c92d8..c09ed55d8a9 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
@@ -106,11 +106,10 @@ public class AnotherFakeApi {
         if (localVarResponse.statusCode()/ 100 != 2) {
           throw getApiException("call123testSpecialTags", localVarResponse);
         }
-        InputStream responseBody = localVarResponse.body();
         return new ApiResponse<Client>(
           localVarResponse.statusCode(),
           localVarResponse.headers().map(),
-          responseBody == null || responseBody.available() < 1 ? null : memberVarObjectMapper.readValue(responseBody, new TypeReference<Client>() {}) // closes the InputStream
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<Client>() {}) // closes the InputStream
         );
       } finally {
       }
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/DefaultApi.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/DefaultApi.java
index 8b164954bc3..6744fdc7ffd 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/DefaultApi.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/DefaultApi.java
@@ -104,11 +104,10 @@ public class DefaultApi {
         if (localVarResponse.statusCode()/ 100 != 2) {
           throw getApiException("fooGet", localVarResponse);
         }
-        InputStream responseBody = localVarResponse.body();
         return new ApiResponse<FooGetDefaultResponse>(
           localVarResponse.statusCode(),
           localVarResponse.headers().map(),
-          responseBody == null || responseBody.available() < 1 ? null : memberVarObjectMapper.readValue(responseBody, new TypeReference<FooGetDefaultResponse>() {}) // closes the InputStream
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<FooGetDefaultResponse>() {}) // closes the InputStream
         );
       } finally {
       }
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeApi.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeApi.java
index 384d478bb3a..7f35d8b2e1e 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeApi.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeApi.java
@@ -115,11 +115,10 @@ public class FakeApi {
         if (localVarResponse.statusCode()/ 100 != 2) {
           throw getApiException("fakeHealthGet", localVarResponse);
         }
-        InputStream responseBody = localVarResponse.body();
         return new ApiResponse<HealthCheckResult>(
           localVarResponse.statusCode(),
           localVarResponse.headers().map(),
-          responseBody == null || responseBody.available() < 1 ? null : memberVarObjectMapper.readValue(responseBody, new TypeReference<HealthCheckResult>() {}) // closes the InputStream
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<HealthCheckResult>() {}) // closes the InputStream
         );
       } finally {
       }
@@ -279,11 +278,10 @@ public class FakeApi {
         if (localVarResponse.statusCode()/ 100 != 2) {
           throw getApiException("fakeOuterBooleanSerialize", localVarResponse);
         }
-        InputStream responseBody = localVarResponse.body();
         return new ApiResponse<Boolean>(
           localVarResponse.statusCode(),
           localVarResponse.headers().map(),
-          responseBody == null || responseBody.available() < 1 ? null : memberVarObjectMapper.readValue(responseBody, new TypeReference<Boolean>() {}) // closes the InputStream
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<Boolean>() {}) // closes the InputStream
         );
       } finally {
       }
@@ -353,11 +351,10 @@ public class FakeApi {
         if (localVarResponse.statusCode()/ 100 != 2) {
           throw getApiException("fakeOuterCompositeSerialize", localVarResponse);
         }
-        InputStream responseBody = localVarResponse.body();
         return new ApiResponse<OuterComposite>(
           localVarResponse.statusCode(),
           localVarResponse.headers().map(),
-          responseBody == null || responseBody.available() < 1 ? null : memberVarObjectMapper.readValue(responseBody, new TypeReference<OuterComposite>() {}) // closes the InputStream
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<OuterComposite>() {}) // closes the InputStream
         );
       } finally {
       }
@@ -427,11 +424,10 @@ public class FakeApi {
         if (localVarResponse.statusCode()/ 100 != 2) {
           throw getApiException("fakeOuterNumberSerialize", localVarResponse);
         }
-        InputStream responseBody = localVarResponse.body();
         return new ApiResponse<BigDecimal>(
           localVarResponse.statusCode(),
           localVarResponse.headers().map(),
-          responseBody == null || responseBody.available() < 1 ? null : memberVarObjectMapper.readValue(responseBody, new TypeReference<BigDecimal>() {}) // closes the InputStream
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<BigDecimal>() {}) // closes the InputStream
         );
       } finally {
       }
@@ -501,11 +497,10 @@ public class FakeApi {
         if (localVarResponse.statusCode()/ 100 != 2) {
           throw getApiException("fakeOuterStringSerialize", localVarResponse);
         }
-        InputStream responseBody = localVarResponse.body();
         return new ApiResponse<String>(
           localVarResponse.statusCode(),
           localVarResponse.headers().map(),
-          responseBody == null || responseBody.available() < 1 ? null : memberVarObjectMapper.readValue(responseBody, new TypeReference<String>() {}) // closes the InputStream
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<String>() {}) // closes the InputStream
         );
       } finally {
       }
@@ -570,11 +565,10 @@ public class FakeApi {
         if (localVarResponse.statusCode()/ 100 != 2) {
           throw getApiException("fakePropertyEnumIntegerSerialize", localVarResponse);
         }
-        InputStream responseBody = localVarResponse.body();
         return new ApiResponse<OuterObjectWithEnumProperty>(
           localVarResponse.statusCode(),
           localVarResponse.headers().map(),
-          responseBody == null || responseBody.available() < 1 ? null : memberVarObjectMapper.readValue(responseBody, new TypeReference<OuterObjectWithEnumProperty>() {}) // closes the InputStream
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<OuterObjectWithEnumProperty>() {}) // closes the InputStream
         );
       } finally {
       }
@@ -903,11 +897,10 @@ public class FakeApi {
         if (localVarResponse.statusCode()/ 100 != 2) {
           throw getApiException("testClientModel", localVarResponse);
         }
-        InputStream responseBody = localVarResponse.body();
         return new ApiResponse<Client>(
           localVarResponse.statusCode(),
           localVarResponse.headers().map(),
-          responseBody == null || responseBody.available() < 1 ? null : memberVarObjectMapper.readValue(responseBody, new TypeReference<Client>() {}) // closes the InputStream
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<Client>() {}) // closes the InputStream
         );
       } finally {
       }
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
index e6c8eab5338..f035fc38721 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/FakeClassnameTags123Api.java
@@ -106,11 +106,10 @@ public class FakeClassnameTags123Api {
         if (localVarResponse.statusCode()/ 100 != 2) {
           throw getApiException("testClassname", localVarResponse);
         }
-        InputStream responseBody = localVarResponse.body();
         return new ApiResponse<Client>(
           localVarResponse.statusCode(),
           localVarResponse.headers().map(),
-          responseBody == null || responseBody.available() < 1 ? null : memberVarObjectMapper.readValue(responseBody, new TypeReference<Client>() {}) // closes the InputStream
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<Client>() {}) // closes the InputStream
         );
       } finally {
       }
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/PetApi.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/PetApi.java
index c31d9a1a2c8..f9d23e700dc 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/PetApi.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/PetApi.java
@@ -269,11 +269,10 @@ public class PetApi {
         if (localVarResponse.statusCode()/ 100 != 2) {
           throw getApiException("findPetsByStatus", localVarResponse);
         }
-        InputStream responseBody = localVarResponse.body();
         return new ApiResponse<List<Pet>>(
           localVarResponse.statusCode(),
           localVarResponse.headers().map(),
-          responseBody == null || responseBody.available() < 1 ? null : memberVarObjectMapper.readValue(responseBody, new TypeReference<List<Pet>>() {}) // closes the InputStream
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<List<Pet>>() {}) // closes the InputStream
         );
       } finally {
       }
@@ -354,11 +353,10 @@ public class PetApi {
         if (localVarResponse.statusCode()/ 100 != 2) {
           throw getApiException("findPetsByTags", localVarResponse);
         }
-        InputStream responseBody = localVarResponse.body();
         return new ApiResponse<Set<Pet>>(
           localVarResponse.statusCode(),
           localVarResponse.headers().map(),
-          responseBody == null || responseBody.available() < 1 ? null : memberVarObjectMapper.readValue(responseBody, new TypeReference<Set<Pet>>() {}) // closes the InputStream
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<Set<Pet>>() {}) // closes the InputStream
         );
       } finally {
       }
@@ -435,11 +433,10 @@ public class PetApi {
         if (localVarResponse.statusCode()/ 100 != 2) {
           throw getApiException("getPetById", localVarResponse);
         }
-        InputStream responseBody = localVarResponse.body();
         return new ApiResponse<Pet>(
           localVarResponse.statusCode(),
           localVarResponse.headers().map(),
-          responseBody == null || responseBody.available() < 1 ? null : memberVarObjectMapper.readValue(responseBody, new TypeReference<Pet>() {}) // closes the InputStream
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<Pet>() {}) // closes the InputStream
         );
       } finally {
       }
@@ -671,11 +668,10 @@ public class PetApi {
         if (localVarResponse.statusCode()/ 100 != 2) {
           throw getApiException("uploadFile", localVarResponse);
         }
-        InputStream responseBody = localVarResponse.body();
         return new ApiResponse<ModelApiResponse>(
           localVarResponse.statusCode(),
           localVarResponse.headers().map(),
-          responseBody == null || responseBody.available() < 1 ? null : memberVarObjectMapper.readValue(responseBody, new TypeReference<ModelApiResponse>() {}) // closes the InputStream
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<ModelApiResponse>() {}) // closes the InputStream
         );
       } finally {
       }
@@ -748,11 +744,10 @@ public class PetApi {
         if (localVarResponse.statusCode()/ 100 != 2) {
           throw getApiException("uploadFileWithRequiredFile", localVarResponse);
         }
-        InputStream responseBody = localVarResponse.body();
         return new ApiResponse<ModelApiResponse>(
           localVarResponse.statusCode(),
           localVarResponse.headers().map(),
-          responseBody == null || responseBody.available() < 1 ? null : memberVarObjectMapper.readValue(responseBody, new TypeReference<ModelApiResponse>() {}) // closes the InputStream
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<ModelApiResponse>() {}) // closes the InputStream
         );
       } finally {
       }
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/StoreApi.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/StoreApi.java
index c54ddcb284d..5e7412d3956 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/StoreApi.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/StoreApi.java
@@ -179,11 +179,10 @@ public class StoreApi {
         if (localVarResponse.statusCode()/ 100 != 2) {
           throw getApiException("getInventory", localVarResponse);
         }
-        InputStream responseBody = localVarResponse.body();
         return new ApiResponse<Map<String, Integer>>(
           localVarResponse.statusCode(),
           localVarResponse.headers().map(),
-          responseBody == null || responseBody.available() < 1 ? null : memberVarObjectMapper.readValue(responseBody, new TypeReference<Map<String, Integer>>() {}) // closes the InputStream
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<Map<String, Integer>>() {}) // closes the InputStream
         );
       } finally {
       }
@@ -247,11 +246,10 @@ public class StoreApi {
         if (localVarResponse.statusCode()/ 100 != 2) {
           throw getApiException("getOrderById", localVarResponse);
         }
-        InputStream responseBody = localVarResponse.body();
         return new ApiResponse<Order>(
           localVarResponse.statusCode(),
           localVarResponse.headers().map(),
-          responseBody == null || responseBody.available() < 1 ? null : memberVarObjectMapper.readValue(responseBody, new TypeReference<Order>() {}) // closes the InputStream
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<Order>() {}) // closes the InputStream
         );
       } finally {
       }
@@ -320,11 +318,10 @@ public class StoreApi {
         if (localVarResponse.statusCode()/ 100 != 2) {
           throw getApiException("placeOrder", localVarResponse);
         }
-        InputStream responseBody = localVarResponse.body();
         return new ApiResponse<Order>(
           localVarResponse.statusCode(),
           localVarResponse.headers().map(),
-          responseBody == null || responseBody.available() < 1 ? null : memberVarObjectMapper.readValue(responseBody, new TypeReference<Order>() {}) // closes the InputStream
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<Order>() {}) // closes the InputStream
         );
       } finally {
       }
diff --git a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/UserApi.java b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/UserApi.java
index 00e46631746..f95345a81a9 100644
--- a/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/UserApi.java
+++ b/samples/client/petstore/java/native/src/main/java/org/openapitools/client/api/UserApi.java
@@ -422,11 +422,10 @@ public class UserApi {
         if (localVarResponse.statusCode()/ 100 != 2) {
           throw getApiException("getUserByName", localVarResponse);
         }
-        InputStream responseBody = localVarResponse.body();
         return new ApiResponse<User>(
           localVarResponse.statusCode(),
           localVarResponse.headers().map(),
-          responseBody == null || responseBody.available() < 1 ? null : memberVarObjectMapper.readValue(responseBody, new TypeReference<User>() {}) // closes the InputStream
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<User>() {}) // closes the InputStream
         );
       } finally {
       }
@@ -497,11 +496,10 @@ public class UserApi {
         if (localVarResponse.statusCode()/ 100 != 2) {
           throw getApiException("loginUser", localVarResponse);
         }
-        InputStream responseBody = localVarResponse.body();
         return new ApiResponse<String>(
           localVarResponse.statusCode(),
           localVarResponse.headers().map(),
-          responseBody == null || responseBody.available() < 1 ? null : memberVarObjectMapper.readValue(responseBody, new TypeReference<String>() {}) // closes the InputStream
+          localVarResponse.body() == null ? null : memberVarObjectMapper.readValue(localVarResponse.body(), new TypeReference<String>() {}) // closes the InputStream
         );
       } finally {
       }