Markus Lutum [http://community.jboss.org/people/mclu] created the discussion "ConcurrentModificationException at ChannelSupport.deliverInternal" To view the discussion, visit: http://community.jboss.org/message/580205#580205 -------------------------------------------------------------- Hi out there. We are using Messaging 1.4.5 GA and got twice this error in production at 2 different systems: Any ideas about the problem? Should we update to 1.4.7? It could be that we had a short network issue on that machine but application and database is on the same machine. Also I whould not expect a concurrentModificationException if this happens. It the network the root cause and what happens with the system if this happend? THX Markus 15:36:11,000 WARN  [org.jboss.jms.server.endpoint.ServerSessionEndpoint] No expiry queue has been configured so removing expired Reference[23298596871307270]:RELIABLE 15:36:11,015 WARN  [org.jboss.jms.server.endpoint.ServerSessionEndpoint] No expiry queue has been configured so removing expired Reference[23298608005775380]:RELIABLE 15:36:11,015 WARN  [org.jboss.jms.server.endpoint.ServerSessionEndpoint] No expiry queue has been configured so removing expired Reference[23298608312483861]:RELIABLE 15:36:11,031 ERROR [org.jboss.messaging.core.impl.ChannelSupport] Queue[26556037/1/2-notifications_mediumretry] Failed to deliver java.util.ConcurrentModificationException         at java.util.LinkedList$ListItr.checkForComodification(Unknown Source)         at java.util.LinkedList$ListItr.remove(Unknown Source)         at org.jboss.messaging.util.prioritylinkedlist.BasicPriorityLinkedList$PriorityLinkedListIterator.remove(BasicPriorityLinkedList.java:295)         at org.jboss.messaging.core.impl.ChannelSupport.deliverInternal(ChannelSupport.java:729)         at org.jboss.messaging.core.impl.MessagingQueue.deliverInternal(MessagingQueue.java:506)         at org.jboss.messaging.core.impl.ChannelSupport.acknowledgeInternal(ChannelSupport.java:844)         at org.jboss.messaging.core.impl.ChannelSupport.acknowledge(ChannelSupport.java:290)         at org.jboss.messaging.core.impl.SimpleDelivery.acknowledge(SimpleDelivery.java:103)         at org.jboss.jms.server.endpoint.ServerSessionEndpoint.expireDelivery(ServerSessionEndpoint.java:1109)         at org.jboss.jms.server.endpoint.ServerConsumerEndpoint.handle(ServerConsumerEndpoint.java:236)         at org.jboss.messaging.core.impl.RoundRobinDistributor.handle(RoundRobinDistributor.java:119)         at org.jboss.messaging.core.impl.MessagingQueue$DistributorWrapper.handle(MessagingQueue.java:583)         at org.jboss.messaging.core.impl.ClusterRoundRobinDistributor.handle(ClusterRoundRobinDistributor.java:79)         at org.jboss.messaging.core.impl.ChannelSupport.deliverInternal(ChannelSupport.java:665)         at org.jboss.messaging.core.impl.MessagingQueue.deliverInternal(MessagingQueue.java:506)         at org.jboss.messaging.core.impl.ChannelSupport.acknowledgeInternal(ChannelSupport.java:844)         at org.jboss.messaging.core.impl.ChannelSupport.acknowledge(ChannelSupport.java:290)         at org.jboss.messaging.core.impl.SimpleDelivery.acknowledge(SimpleDelivery.java:103)         at org.jboss.jms.server.endpoint.ServerSessionEndpoint.expireDelivery(ServerSessionEndpoint.java:1109)         at org.jboss.jms.server.endpoint.ServerConsumerEndpoint.handle(ServerConsumerEndpoint.java:236)         at org.jboss.messaging.core.impl.RoundRobinDistributor.handle(RoundRobinDistributor.java:119)         at org.jboss.messaging.core.impl.MessagingQueue$DistributorWrapper.handle(MessagingQueue.java:583)         at org.jboss.messaging.core.impl.ClusterRoundRobinDistributor.handle(ClusterRoundRobinDistributor.java:79)         at org.jboss.messaging.core.impl.ChannelSupport.deliverScheduled(ChannelSupport.java:763)         at org.jboss.messaging.core.impl.ChannelSupport$DeliverRefTimeoutTarget.timedOut(ChannelSupport.java:1151)         at org.jboss.util.timeout.TimeoutFactory$TimeoutWorker.run(TimeoutFactory.java:265)         at org.jboss.util.threadpool.RunnableTaskWrapper.run(RunnableTaskWrapper.java:148)         at EDU.oswego.cs.dl.util.concurrent.PooledExecutor$Worker.run(PooledExecutor.java:756)         at java.lang.Thread.run(Unknown Source) -------------------------------------------------------------- Reply to this message by going to Community [http://community.jboss.org/message/580205#580205] Start a new discussion in JBoss Messaging at Community [http://community.jboss.org/choose-container!input.jspa?contentType=1&...]