There is a potential to have a deadlock if two threads are invoking logging handlers and both threads end up invoking the error handler for their logging handler.  

The way the deadlock works is 

- Thread 1 invokes the error handler
- The error handler writes to System.out.println
- This is routed back into the logging subsystem via jboss-stdio
- As usual, JBoss LogManager will send the message to all appropriate handlers
- The thread halts, waiting on a lock for the handler locked by thread 2

- Thread 2 is running in a different handler for which it has a lock
- This lock must have been obtained after thread 1 invoked this handler but before the error handler from thread 1 tried to invoke the same handler
- This handler also invokes its error handler
- The error handler halts, waiting on the lock for System.out, held by thread 1