Fixed a bug that a NullPointerException is thrown when the descriptio…

springdoc-openapi-starter-common/src/main/java/org/springdoc/core/service/RequestBodyService.java

@@ -288,13 +288,12 @@ else if (!methodAttributes.isWithResponseBodySchemaDoc()) {
 			mergeContent(requestBody, methodAttributes, schema);
 		}
 
-
 		// Add requestBody javadoc
 		if (StringUtils.isBlank(requestBody.getDescription()) && parameterBuilder.getJavadocProvider() != null
 				&& parameterBuilder.isRequestBodyPresent(parameterInfo)) {
 			String paramJavadocDescription = parameterBuilder.getParamJavadoc(parameterBuilder.getJavadocProvider(), parameterInfo.getMethodParameter());
 			if (!StringUtils.isBlank(paramJavadocDescription)) {
-				requestBodyInfo.getRequestBody().setDescription(paramJavadocDescription);
+				requestBody.setDescription(paramJavadocDescription);
 			}
 		}
 		return requestBody;

springdoc-openapi-tests/springdoc-openapi-javadoc-tests/src/test/java/test/org/springdoc/api/app168/DescriptionFieldInRequestBodyIsNullController.java

@@ -0,0 +1,45 @@
+/*
+ *
+ *  * Copyright 2019-2023 the original author or authors.
+ *  *
+ *  * Licensed under the Apache License, Version 2.0 (the "License");
+ *  * you may not use this file except in compliance with the License.
+ *  * You may obtain a copy of the License at
+ *  *
+ *  *      https://www.apache.org/licenses/LICENSE-2.0
+ *  *
+ *  * Unless required by applicable law or agreed to in writing, software
+ *  * distributed under the License is distributed on an "AS IS" BASIS,
+ *  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  * See the License for the specific language governing permissions and
+ *  * limitations under the License.
+ *
+ */
+
+package test.org.springdoc.api.app168;
+
+import io.swagger.v3.oas.annotations.media.Content;
+import io.swagger.v3.oas.annotations.media.Schema;
+
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * If the RequestBody description field is null, get the description from the javadoc.
+ */
+@RestController
+@RequestMapping("description-in-requestbody-is-null")
+public class DescriptionFieldInRequestBodyIsNullController {
+
+	/**
+	 * Person person.
+	 *
+	 * @param person the person
+	 */
+	@PostMapping
+	public void person(
+			@io.swagger.v3.oas.annotations.parameters.RequestBody(content = @Content(schema = @Schema(implementation = Person.class))) @RequestBody Person person) {
+	}
+}

springdoc-openapi-tests/springdoc-openapi-javadoc-tests/src/test/java/test/org/springdoc/api/app168/Person.java

@@ -0,0 +1,29 @@
+package test.org.springdoc.api.app168;
+
+/**
+ * The type Person.
+ */
+public class Person {
+	/**
+	 * The Id.
+	 */
+	private long id;
+
+	/**
+	 * Gets id.
+	 *
+	 * @return the id
+	 */
+	public long getId() {
+		return id;
+	}
+
+	/**
+	 * Sets id.
+	 *
+	 * @param id the id
+	 */
+	public void setId(long id) {
+		this.id = id;
+	}
+}

springdoc-openapi-tests/springdoc-openapi-javadoc-tests/src/test/java/test/org/springdoc/api/app168/SpringDocApp168Test.java

@@ -0,0 +1,36 @@
+/*
+ *
+ *  * Copyright 2019-2023 the original author or authors.
+ *  *
+ *  * Licensed under the Apache License, Version 2.0 (the "License");
+ *  * you may not use this file except in compliance with the License.
+ *  * You may obtain a copy of the License at
+ *  *
+ *  *      https://www.apache.org/licenses/LICENSE-2.0
+ *  *
+ *  * Unless required by applicable law or agreed to in writing, software
+ *  * distributed under the License is distributed on an "AS IS" BASIS,
+ *  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  * See the License for the specific language governing permissions and
+ *  * limitations under the License.
+ *
+ */
+
+package test.org.springdoc.api.app168;
+
+import test.org.springdoc.api.AbstractSpringDocTest;
+
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * The type Spring doc app 168 test.
+ */
+public class SpringDocApp168Test extends AbstractSpringDocTest {
+
+	/**
+	 * The type Spring doc test app.
+	 */
+	@SpringBootApplication
+	static class SpringDocTestApp {
+	}
+}

springdoc-openapi-tests/springdoc-openapi-javadoc-tests/src/test/resources/results/app168.json

@@ -0,0 +1,63 @@
+{
+  "openapi": "3.0.1",
+  "info": {
+    "title": "OpenAPI definition",
+    "version": "v0"
+  },
+  "servers": [
+    {
+      "url": "http://localhost",
+      "description": "Generated server url"
+    }
+  ],
+  "tags": [
+    {
+      "name": "description-field-in-request-body-is-null-controller",
+      "description": "If the RequestBody description field is null, get the description from the javadoc."
+    }
+  ],
+  "paths": {
+    "/description-in-requestbody-is-null": {
+      "post": {
+        "tags": [
+          "description-field-in-request-body-is-null-controller"
+        ],
+        "operationId": "person",
+        "summary": "Person person.",
+        "description": "Person person.",
+        "operationId": "person",
+        "requestBody": {
+          "description": "the person",
+          "content": {
+            "application/json": {
+              "schema": {
+                "$ref": "#/components/schemas/Person"
+              }
+            }
+          },
+          "required": true
+        },
+        "responses": {
+          "200": {
+            "description": "OK"
+          }
+        }
+      }
+    }
+  },
+  "components": {
+    "schemas": {
+      "Person": {
+        "type": "object",
+        "properties": {
+          "id": {
+            "type": "integer",
+            "description": "The Id.",
+            "format": "int64"
+          }
+        },
+        "description": "The type Person."
+      }
+    }
+  }
+}