fixed JmsException/JmsUtils to fully avoid NPEs in case of cause messages being null

org.springframework.jms/src/main/java/org/springframework/jms/JmsException.java

 /*
- * Copyright 2002-2008 the original author or authors.
+ * 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.
@@ -84,8 +84,12 @@ public abstract class JmsException extends NestedRuntimeException {
 		Throwable cause = getCause();
 		if (cause instanceof JMSException) {
 			Exception linkedEx = ((JMSException) cause).getLinkedException();
-			if (linkedEx != null && cause.getMessage().indexOf(linkedEx.getMessage()) == -1) {
-				message = message + "; nested exception is " + linkedEx;
+			if (linkedEx != null) {
+				String linkedMessage = linkedEx.getMessage();
+				String causeMessage = cause.getMessage();
+				if (linkedMessage != null && (causeMessage == null || !causeMessage.contains(linkedMessage))) {
+					message = message + "; nested exception is " + linkedEx;
+				}
 			}
 		}
 		return message;

org.springframework.jms/src/main/java/org/springframework/jms/listener/DefaultMessageListenerContainer.java

@@ -712,7 +712,7 @@ public class DefaultMessageListenerContainer extends AbstractPollingMessageListe
 	/**
 	 * Handle the given exception that arose during setup of a listener.
 	 * Called for every such exception in every concurrent listener.
-	 * <p>The default implementation logs the exception at error level
+	 * <p>The default implementation logs the exception at info level
 	 * if not recovered yet, and at debug level if already recovered.
 	 * Can be overridden in subclasses.
 	 * @param ex the exception to handle

org.springframework.jms/src/main/java/org/springframework/jms/support/JmsUtils.java

 /*
- * Copyright 2002-2008 the original author or authors.
+ * 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.
@@ -256,8 +256,11 @@ public abstract class JmsUtils {
 			if (message == null) {
 				message = linkedEx.toString();
 			}
-			else if (!message.contains(linkedEx.getMessage())) {
-				message = message + "; nested exception is " + linkedEx;
+			else {
+				String linkedMessage = linkedEx.getMessage();
+				if (linkedMessage != null && !message.contains(linkedMessage)) {
+					message = message + "; nested exception is " + linkedEx;
+				}
 			}
 		}
 		return message;