fixed for http://issues.apache.org/activemq/browse/AMQ-1042

git-svn-id: https://svn.apache.org/repos/asf/incubator/activemq/trunk@473647 13f79535-47bb-0310-9956-ffa450edef68

activemq-core/src/main/java/org/apache/activemq/ActiveMQMessageConsumer.java

@@ -856,6 +856,9 @@ public class ActiveMQMessageConsumer implements MessageAvailableConsumer, StatsC
 	                }
 	            }
             }
+            // yeild here so that a thread trying to stop unconsumedMessages has 
+            // a chance of getting prioritized head of this thread that is in a dispatch loop.
+            Thread.yield();            
         } catch (Exception e) {
         	session.connection.onAsyncException(e);
         }