A hang is usually caused by one of the following:

A deadlock

Some thread/transaction is not giving up a locked resource

A livelock

Some thread/transaction are continually trying to get a number of locks but they can never complete the

whole process and the retry is infinite.

A loop

You have some code "spinning" in a loop that will never finish.

A JVM/OS bug

There is a problem with the underlying locking primitives, either of the operating system, the c library

or the way the JVM is using them.

Analysis

To analyse the problem, you need to get some thread dumps. Preferably more than one a few seconds apart. Then analyse the dump for:

• Threads that are waiting for locks held by other threads with the other threads not moving (deadlock)

• Threads waiting for locks that are not held by anybody (JVM/OS bug)

• Threads continually repeating the same code very quickly, accompanied by high cpu utilization (loop)

Is it a JBoss problem

If the problem is JBoss code, post a bug report with thread dumps

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