[OPENEJB-1248] DiscoveryRegistry doesn't work (ConcurrentModificationException)

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Abandoned
• Affects Version/s: 3.1.x
• Fix Version/s: 3.1.x
• Assignee: Unassigned
• Reporter: David Jencks
• Created: 28/Mar/10 23:24
• Updated: 11/Aug/11 03:02
• Resolved: 11/Aug/11 03:02

Description

I get:

Module 35/41 org.apache.geronimo.configs/openejb-deployer/3.0-SNAPSHOT/car Exception in thread "Multicast Discovery Agent Notifier" java.util.ConcurrentModificationException
at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372)
at java.util.AbstractList$Itr.next(AbstractList.java:343)
at java.util.Collections$UnmodifiableCollection$1.next(Collections.java:1010)
at org.apache.openejb.server.DiscoveryRegistry.serviceAdded(DiscoveryRegistry.java:121)
at org.apache.openejb.server.discovery.MulticastDiscoveryAgent$Listener$3.run(MulticastDiscoveryAgent.java:437)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:637)

Looking at the code it clearly needs a lot of synchronization. Perhaps the author thought that

List<DiscoveryListener> getListeners()

{ return Collections.unmodifiableList(listeners); }

would copy the list of listeners instead of providing a view that reflects all changes to the underlying list.