From 9caf672f2160b88d3285cb78d131bec9ea6c1fbe Mon Sep 17 00:00:00 2001
From: Juergen Hoeller <jhoeller@vmware.com>
Date: Wed, 31 Oct 2012 08:53:29 +0100
Subject: [PATCH] Added proper synchronization and not-null check to
 SimpleMessageListenerContainer's doShutdown

Issue: SPR-9930
---
 .../SimpleMessageListenerContainer.java        | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/org.springframework.jms/src/main/java/org/springframework/jms/listener/SimpleMessageListenerContainer.java b/org.springframework.jms/src/main/java/org/springframework/jms/listener/SimpleMessageListenerContainer.java
index 82d953564b1..3bd88b84baa 100644
--- a/org.springframework.jms/src/main/java/org/springframework/jms/listener/SimpleMessageListenerContainer.java
+++ b/org.springframework.jms/src/main/java/org/springframework/jms/listener/SimpleMessageListenerContainer.java
@@ -351,13 +351,17 @@ public class SimpleMessageListenerContainer extends AbstractMessageListenerConta
 	 */
 	@Override
 	protected void doShutdown() throws JMSException {
-		logger.debug("Closing JMS MessageConsumers");
-		for (MessageConsumer consumer : this.consumers) {
-			JmsUtils.closeMessageConsumer(consumer);
-		}
-		logger.debug("Closing JMS Sessions");
-		for (Session session : this.sessions) {
-			JmsUtils.closeSession(session);
+		synchronized (this.consumersMonitor) {
+			if (this.consumers != null) {
+				logger.debug("Closing JMS MessageConsumers");
+				for (MessageConsumer consumer : this.consumers) {
+					JmsUtils.closeMessageConsumer(consumer);
+				}
+				logger.debug("Closing JMS Sessions");
+				for (Session session : this.sessions) {
+					JmsUtils.closeSession(session);
+				}
+			}
 		}
 	}