I was executing a test which starts and stops servers in a loop, and I noticed on a stack trace there were very many AIO poller/writer threads.

Looking at the code in AIOSequentialFileFactory it seems the following two executors never get shut down:

 private final Executor writeExecutor = Executors.newSingleThreadExecutor(new HornetQThreadFactory("HornetQ-AIO-writer-pool" + System.identityHashCode(this),
 true));

 private final Executor pollerExecutor = Executors.newCachedThreadPool(new HornetQThreadFactory("HornetQ-AIO-poller-pool" + System.identityHashCode(this),

This very bad practice. All executors must be shutdown synchronously when the module stops and termination should be waited for.