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 582b58938df..0f63601e063 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
@@ -4656,18 +4656,19 @@ public class DefaultCodegen implements CodegenConfig {
                     bodyParameterName = (String) op.vendorExtensions.get("x-codegen-request-body-name");
                 }
                 bodyParam = fromRequestBody(requestBody, imports, bodyParameterName);
-                bodyParam.description = escapeText(requestBody.getDescription());
-                postProcessParameter(bodyParam);
 
-                bodyParams.add(bodyParam);
+                if (bodyParam != null) {
+                    bodyParam.description = escapeText(requestBody.getDescription());
+                    postProcessParameter(bodyParam);
+                    bodyParams.add(bodyParam);
+                    if (prependFormOrBodyParameters) {
+                        allParams.add(bodyParam);
+                    }
 
-                if (prependFormOrBodyParameters) {
-                    allParams.add(bodyParam);
-                }
-
-                // add example
-                if (schemas != null && !isSkipOperationExample()) {
-                    op.requestBodyExamples = new ExampleGenerator(schemas, this.openAPI).generate(null, new ArrayList<>(getConsumesInfo(this.openAPI, operation)), bodyParam.baseType);
+                    // add example
+                    if (schemas != null && !isSkipOperationExample()) {
+                        op.requestBodyExamples = new ExampleGenerator(schemas, this.openAPI).generate(null, new ArrayList<>(getConsumesInfo(this.openAPI, operation)), bodyParam.baseType);
+                    }
                 }
             }
         }
@@ -7596,6 +7597,10 @@ public class DefaultCodegen implements CodegenConfig {
         String name = null;
         LOGGER.debug("Request body = {}", body);
         Schema schema = ModelUtils.getSchemaFromRequestBody(body);
+        if (schema == null) {
+            LOGGER.error("Schema cannot be null in the request body: {}", body);
+            return null;
+        }
         Schema original = null;
         // check if it's allOf (only 1 sub schema) with or without default/nullable/etc set in the top level
         if (ModelUtils.isAllOf(schema) && schema.getAllOf().size() == 1 &&
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/ModelUtils.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/ModelUtils.java
index 06c645a5254..58830aced88 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/ModelUtils.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/ModelUtils.java
@@ -1848,7 +1848,7 @@ public class ModelUtils {
      * @return true if allOf is not empty
      */
     public static boolean hasAllOf(Schema schema) {
-        if (schema.getAllOf() != null && !schema.getAllOf().isEmpty()) {
+        if (schema != null && schema.getAllOf() != null && !schema.getAllOf().isEmpty()) {
             return true;
         }
 
diff --git a/modules/openapi-generator/src/test/resources/3_0/java/petstore-with-fake-endpoints-models-for-testing-okhttp-gson.yaml b/modules/openapi-generator/src/test/resources/3_0/java/petstore-with-fake-endpoints-models-for-testing-okhttp-gson.yaml
index f4332f5fe3b..2e02cb701a0 100644
--- a/modules/openapi-generator/src/test/resources/3_0/java/petstore-with-fake-endpoints-models-for-testing-okhttp-gson.yaml
+++ b/modules/openapi-generator/src/test/resources/3_0/java/petstore-with-fake-endpoints-models-for-testing-okhttp-gson.yaml
@@ -1196,6 +1196,52 @@ paths:
       responses:
         200:
           description: OK
+  /fake/null-request-body:
+    get:
+      tags:
+        - another_fake
+      summary: null request body
+      operationId: null-request-body
+      parameters:
+        - name: Accept-Language
+          in: header
+          schema:
+            type: string
+            example: application/json
+      requestBody:
+        content:
+          text/plain:
+            examples:
+              Generar Orden por External ID:
+                value: |-
+                  {
+                      "external_reference": "{{external_order_ref}}",
+                      "notification_url": "www.yourserver.com/yourendpoint",
+                      "sponsor_id": 446566691,
+                      "items": [
+                          {
+                              "title": "Papas frita",
+                              "currency_id": "{{currency_id}}",
+                              "unit_price": 6000,
+                              "quantity": 1
+                          },
+                          {
+                              "title": "Gaseosa",
+                              "currency_id": "{{currency_id}}",
+                              "unit_price": 3000,
+                              "quantity": 1
+                          }
+                      ]/*,
+                      "taxes": [
+                          {
+                              "value": 0,
+                              "type": "IVA"
+                          }
+                      ]*/
+                  }
+      responses:
+        '200':
+          description: ''
   /values:
     get:
       tags:
diff --git a/samples/client/petstore/java/okhttp-gson/README.md b/samples/client/petstore/java/okhttp-gson/README.md
index 4b2ed954eaf..5bb2a315d28 100644
--- a/samples/client/petstore/java/okhttp-gson/README.md
+++ b/samples/client/petstore/java/okhttp-gson/README.md
@@ -116,6 +116,7 @@ Class | Method | HTTP request | Description
 *AnotherFakeApi* | [**call123testSpecialTags**](docs/AnotherFakeApi.md#call123testSpecialTags) | **PATCH** /another-fake/dummy | To test special tags
 *AnotherFakeApi* | [**getParameterArrayNumber**](docs/AnotherFakeApi.md#getParameterArrayNumber) | **GET** /fake/parameter-array-number | parameter array number default value
 *AnotherFakeApi* | [**getParameterStringNumber**](docs/AnotherFakeApi.md#getParameterStringNumber) | **GET** /fake/parameter-string-number | parameter string number
+*AnotherFakeApi* | [**nullRequestBody**](docs/AnotherFakeApi.md#nullRequestBody) | **GET** /fake/null-request-body | null request body
 *DefaultApi* | [**fooGet**](docs/DefaultApi.md#fooGet) | **GET** /foo | 
 *FakeApi* | [**fakeHealthGet**](docs/FakeApi.md#fakeHealthGet) | **GET** /fake/health | Health check endpoint
 *FakeApi* | [**fakeOuterBooleanSerialize**](docs/FakeApi.md#fakeOuterBooleanSerialize) | **POST** /fake/outer/boolean | 
diff --git a/samples/client/petstore/java/okhttp-gson/api/openapi.yaml b/samples/client/petstore/java/okhttp-gson/api/openapi.yaml
index 37b2af48ba6..d8888a185e4 100644
--- a/samples/client/petstore/java/okhttp-gson/api/openapi.yaml
+++ b/samples/client/petstore/java/okhttp-gson/api/openapi.yaml
@@ -1230,6 +1230,56 @@ paths:
       tags:
       - another_fake
       x-accepts: application/json
+  /fake/null-request-body:
+    get:
+      operationId: null-request-body
+      parameters:
+      - explode: false
+        in: header
+        name: Accept-Language
+        required: false
+        schema:
+          example: application/json
+          type: string
+        style: simple
+      requestBody:
+        content:
+          text/plain:
+            examples:
+              Generar Orden por External ID:
+                value: |-
+                  {
+                      "external_reference": "{{external_order_ref}}",
+                      "notification_url": "www.yourserver.com/yourendpoint",
+                      "sponsor_id": 446566691,
+                      "items": [
+                          {
+                              "title": "Papas frita",
+                              "currency_id": "{{currency_id}}",
+                              "unit_price": 6000,
+                              "quantity": 1
+                          },
+                          {
+                              "title": "Gaseosa",
+                              "currency_id": "{{currency_id}}",
+                              "unit_price": 3000,
+                              "quantity": 1
+                          }
+                      ]/*,
+                      "taxes": [
+                          {
+                              "value": 0,
+                              "type": "IVA"
+                          }
+                      ]*/
+                  }
+      responses:
+        "200":
+          description: ""
+      summary: null request body
+      tags:
+      - another_fake
+      x-accepts: application/json
   /values:
     get:
       description: ""
diff --git a/samples/client/petstore/java/okhttp-gson/docs/AnotherFakeApi.md b/samples/client/petstore/java/okhttp-gson/docs/AnotherFakeApi.md
index 6cca209c72b..d21e29ab092 100644
--- a/samples/client/petstore/java/okhttp-gson/docs/AnotherFakeApi.md
+++ b/samples/client/petstore/java/okhttp-gson/docs/AnotherFakeApi.md
@@ -7,6 +7,7 @@ All URIs are relative to *http://petstore.swagger.io:80/v2*
 | [**call123testSpecialTags**](AnotherFakeApi.md#call123testSpecialTags) | **PATCH** /another-fake/dummy | To test special tags |
 | [**getParameterArrayNumber**](AnotherFakeApi.md#getParameterArrayNumber) | **GET** /fake/parameter-array-number | parameter array number default value |
 | [**getParameterStringNumber**](AnotherFakeApi.md#getParameterStringNumber) | **GET** /fake/parameter-string-number | parameter string number |
+| [**nullRequestBody**](AnotherFakeApi.md#nullRequestBody) | **GET** /fake/null-request-body | null request body |
 
 
 <a id="call123testSpecialTags"></a>
@@ -189,3 +190,62 @@ No authorization required
 |-------------|-------------|------------------|
 | **200** | OK |  -  |
 
+<a id="nullRequestBody"></a>
+# **nullRequestBody**
+> nullRequestBody(acceptLanguage)
+
+null request body
+
+### 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.AnotherFakeApi;
+
+public class Example {
+  public static void main(String[] args) {
+    ApiClient defaultClient = Configuration.getDefaultApiClient();
+    defaultClient.setBasePath("http://petstore.swagger.io:80/v2");
+
+    AnotherFakeApi apiInstance = new AnotherFakeApi(defaultClient);
+    String acceptLanguage = "application/json"; // String | 
+    try {
+      apiInstance.nullRequestBody(acceptLanguage);
+    } catch (ApiException e) {
+      System.err.println("Exception when calling AnotherFakeApi#nullRequestBody");
+      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 |
+|------------- | ------------- | ------------- | -------------|
+| **acceptLanguage** | **String**|  | [optional] |
+
+### Return type
+
+null (empty response body)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+ - **Content-Type**: text/plain
+ - **Accept**: Not defined
+
+### HTTP response details
+| Status code | Description | Response headers |
+|-------------|-------------|------------------|
+| **200** |  |  -  |
+
diff --git a/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/api/AnotherFakeApi.java b/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
index f7529bc7476..a58d4bf127b 100644
--- a/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
+++ b/samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/api/AnotherFakeApi.java
@@ -438,4 +438,121 @@ public class AnotherFakeApi {
         localVarApiClient.executeAsync(localVarCall, _callback);
         return localVarCall;
     }
+    /**
+     * Build call for nullRequestBody
+     * @param acceptLanguage  (optional)
+     * @param _callback Callback for upload/download progress
+     * @return Call to execute
+     * @throws ApiException If fail to serialize the request body object
+     * @http.response.details
+     <table summary="Response Details" border="1">
+        <tr><td> Status Code </td><td> Description </td><td> Response Headers </td></tr>
+        <tr><td> 200 </td><td>  </td><td>  -  </td></tr>
+     </table>
+     */
+    public okhttp3.Call nullRequestBodyCall(String acceptLanguage, final ApiCallback _callback) throws ApiException {
+        String basePath = null;
+        // Operation Servers
+        String[] localBasePaths = new String[] {  };
+
+        // Determine Base Path to Use
+        if (localCustomBaseUrl != null){
+            basePath = localCustomBaseUrl;
+        } else if ( localBasePaths.length > 0 ) {
+            basePath = localBasePaths[localHostIndex];
+        } else {
+            basePath = null;
+        }
+
+        Object localVarPostBody = null;
+
+        // create path and map variables
+        String localVarPath = "/fake/null-request-body";
+
+        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>();
+
+        if (acceptLanguage != null) {
+            localVarHeaderParams.put("Accept-Language", localVarApiClient.parameterToString(acceptLanguage));
+        }
+
+        final String[] localVarAccepts = {
+        };
+        final String localVarAccept = localVarApiClient.selectHeaderAccept(localVarAccepts);
+        if (localVarAccept != null) {
+            localVarHeaderParams.put("Accept", localVarAccept);
+        }
+
+        final String[] localVarContentTypes = {
+            "text/plain"
+        };
+        final String localVarContentType = localVarApiClient.selectHeaderContentType(localVarContentTypes);
+        if (localVarContentType != null) {
+            localVarHeaderParams.put("Content-Type", localVarContentType);
+        }
+
+        String[] localVarAuthNames = new String[] {  };
+        return localVarApiClient.buildCall(basePath, localVarPath, "GET", localVarQueryParams, localVarCollectionQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAuthNames, _callback);
+    }
+
+    @SuppressWarnings("rawtypes")
+    private okhttp3.Call nullRequestBodyValidateBeforeCall(String acceptLanguage, final ApiCallback _callback) throws ApiException {
+        return nullRequestBodyCall(acceptLanguage, _callback);
+
+    }
+
+    /**
+     * null request body
+     * 
+     * @param acceptLanguage  (optional)
+     * @throws ApiException If fail to call the API, e.g. server error or cannot deserialize the response body
+     * @http.response.details
+     <table summary="Response Details" border="1">
+        <tr><td> Status Code </td><td> Description </td><td> Response Headers </td></tr>
+        <tr><td> 200 </td><td>  </td><td>  -  </td></tr>
+     </table>
+     */
+    public void nullRequestBody(String acceptLanguage) throws ApiException {
+        nullRequestBodyWithHttpInfo(acceptLanguage);
+    }
+
+    /**
+     * null request body
+     * 
+     * @param acceptLanguage  (optional)
+     * @return ApiResponse&lt;Void&gt;
+     * @throws ApiException If fail to call the API, e.g. server error or cannot deserialize the response body
+     * @http.response.details
+     <table summary="Response Details" border="1">
+        <tr><td> Status Code </td><td> Description </td><td> Response Headers </td></tr>
+        <tr><td> 200 </td><td>  </td><td>  -  </td></tr>
+     </table>
+     */
+    public ApiResponse<Void> nullRequestBodyWithHttpInfo(String acceptLanguage) throws ApiException {
+        okhttp3.Call localVarCall = nullRequestBodyValidateBeforeCall(acceptLanguage, null);
+        return localVarApiClient.execute(localVarCall);
+    }
+
+    /**
+     * null request body (asynchronously)
+     * 
+     * @param acceptLanguage  (optional)
+     * @param _callback The callback to be executed when the API call finishes
+     * @return The request call
+     * @throws ApiException If fail to process the API call, e.g. serializing the request body object
+     * @http.response.details
+     <table summary="Response Details" border="1">
+        <tr><td> Status Code </td><td> Description </td><td> Response Headers </td></tr>
+        <tr><td> 200 </td><td>  </td><td>  -  </td></tr>
+     </table>
+     */
+    public okhttp3.Call nullRequestBodyAsync(String acceptLanguage, final ApiCallback<Void> _callback) throws ApiException {
+
+        okhttp3.Call localVarCall = nullRequestBodyValidateBeforeCall(acceptLanguage, _callback);
+        localVarApiClient.executeAsync(localVarCall, _callback);
+        return localVarCall;
+    }
 }