ReplicatedHashMap does this at line 587;

for(Notification notif: notifs)
notif.contentsSet(map);

which causes a ConcurrentModificationException if the 'notifs' list is being modified during the execution. This class should use an Iterator over the 'notifs' list instead. There are several places where this occurs but this is illustrative.

2007-11-06 15:47:07,948 ERROR [Multiplexer,udp,192.168.164.229:34526] log.GeronimoLog (GeronimoLog.java:108) - uncaught exception in Thread[Multiplexer,udp,192.168.164.229:34526,10,MultiplexerThreads] (thread group=org.jgroups.util.Util$1[name=JGroups,maxpri=10] )
java.util.ConcurrentModificationException
at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372)
at java.util.AbstractList$Itr.next(AbstractList.java:343)
at org.jgroups.blocks.ReplicatedHashMap._putAll(ReplicatedHashMap.java:587)
at org.jgroups.blocks.ReplicatedHashMap.setState(ReplicatedHashMap.java:716)
at org.jgroups.blocks.MessageDispatcher$ProtocolAdapter.handleUpEvent(MessageDispatcher.java:645)
at org.jgroups.blocks.MessageDispatcher$ProtocolAdapter.up(MessageDispatcher.java:745)
at org.jgroups.JChannel.up(JChannel.java:1069)
at org.jgroups.mux.Multiplexer$Task.run(Multiplexer.java:1026)
at org.jgroups.mux.Multiplexer$ExecuteTask.run(Multiplexer.java:1050)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:885)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
at java.lang.Thread.run(Thread.java:619)