Timeout exceptions as RuntimeExceptions

Issue: SPR-14669
(cherry picked from commit 6dc1898)

spring-messaging/src/main/java/org/springframework/messaging/simp/stomp/ConnectionLostException.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2015 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -23,7 +23,7 @@ package org.springframework.messaging.simp.stomp;
  * @since 4.2
  */
 @SuppressWarnings("serial")
-public class ConnectionLostException extends Exception {
+public class ConnectionLostException extends RuntimeException {
 
 	public ConnectionLostException(String message) {
 		super(message);

spring-web/src/main/java/org/springframework/web/context/request/async/AsyncRequestTimeoutException.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.springframework.web.context.request.async;
 
 /**
@@ -29,6 +30,6 @@ package org.springframework.web.context.request.async;
  * @since 4.2.8
  */
 @SuppressWarnings("serial")
-public class AsyncRequestTimeoutException extends Exception {
+public class AsyncRequestTimeoutException extends RuntimeException {
 
 }

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/ResponseEntityExceptionHandler.java

@@ -186,7 +186,9 @@ public abstract class ResponseEntityExceptionHandler {
 					(AsyncRequestTimeoutException) ex, headers, status, request);
 		}
 		else {
-			logger.warn("Unknown exception type: " + ex.getClass().getName());
+			if (logger.isWarnEnabled()) {
+				logger.warn("Unknown exception type: " + ex.getClass().getName());
+			}
 			HttpStatus status = HttpStatus.INTERNAL_SERVER_ERROR;
 			return handleExceptionInternal(ex, null, headers, status, request);
 		}