SPR-5767 - Misleading error message in HandlerMethodInvoker.resolveRequestBody()

org.springframework.web.servlet/src/main/java/org/springframework/web/bind/annotation/support/HandlerMethodInvoker.java

@@ -437,7 +437,6 @@ public class HandlerMethodInvoker {
 
 	/**
 	 * Resolves the given {@link RequestBody @RequestBody} annotation.
-	 * Throws an UnsupportedOperationException by default.
 	 */
 	@SuppressWarnings("unchecked")
 	protected Object resolveRequestBody(MethodParameter methodParam, NativeWebRequest webRequest, Object handler)
@@ -447,7 +446,7 @@ public class HandlerMethodInvoker {
 		Class paramType = methodParam.getParameterType();
 		MediaType contentType = inputMessage.getHeaders().getContentType();
 		if (contentType == null) {
-			throw new IllegalStateException("Cannot extract response: no Content-Type found");
+			throw new HttpMediaTypeNotSupportedException("Cannot extract @RequestBody: no Content-Type found");
 		}
 		List<MediaType> allSupportedMediaTypes = new ArrayList<MediaType>();
 		for (HttpMessageConverter<?> messageConverter : messageConverters) {

org.springframework.web.servlet/src/main/java/org/springframework/web/servlet/mvc/support/DefaultHandlerExceptionResolver.java

@@ -29,6 +29,7 @@ import org.springframework.core.Ordered;
 import org.springframework.http.MediaType;
 import org.springframework.http.converter.HttpMessageNotReadableException;
 import org.springframework.http.converter.HttpMessageNotWritableException;
+import org.springframework.util.CollectionUtils;
 import org.springframework.util.StringUtils;
 import org.springframework.web.HttpMediaTypeNotSupportedException;
 import org.springframework.web.HttpRequestMethodNotSupportedException;
@@ -187,7 +188,7 @@ public class DefaultHandlerExceptionResolver extends AbstractHandlerExceptionRes
 
 		response.sendError(HttpServletResponse.SC_UNSUPPORTED_MEDIA_TYPE);
 		List<MediaType> mediaTypes = ex.getSupportedMediaTypes();
-		if (mediaTypes != null) {
+		if (!CollectionUtils.isEmpty(mediaTypes)) {
 			response.setHeader("Accept", MediaType.toString(mediaTypes));
 		}
 		return new ModelAndView();

org.springframework.web/src/main/java/org/springframework/web/HttpMediaTypeNotSupportedException.java

@@ -1,5 +1,22 @@
+/*
+ * Copyright 2002-2009 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
+ *
+ *      http://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 org.springframework.web;
 
+import java.util.Collections;
 import java.util.List;
 import javax.servlet.ServletException;
 
@@ -7,17 +24,26 @@ import org.springframework.http.MediaType;
 
 /**
  * Exception thrown when a client POSTs or PUTs content 
- * not supported by request handler does not support a
- * specific request method.
+ * not supported by request handler.
  *
  * @author Arjen Poutsma
  * @since 3.0
  */
 public class HttpMediaTypeNotSupportedException extends ServletException {
 
-	private MediaType contentType;
+	private final MediaType contentType;
 
-	private List<MediaType> supportedMediaTypes;
+	private final List<MediaType> supportedMediaTypes;
+
+	/**
+	 * Create a new HttpMediaTypeNotSupportedException.
+	 * @param message the exception message
+	 */
+	public HttpMediaTypeNotSupportedException(String message) {
+		super(message);
+		this.contentType = null;
+		this.supportedMediaTypes = Collections.emptyList();
+	}
 
 	/**
 	 * Create a new HttpMediaTypeNotSupportedException.