I get a WARNing that a connection error occured

Normally

This means that JBoss either detected that an error occured or was notified of the error by a resource adapter using the

ConnectionEventListener.connectionErrorOccured()

callback.

"Bug" in 4.0.2

In 4.0.2 and previously for some other error conditions, JBoss was warning about an error during the close operation. You can see this when it says state=DESTROYED.

This is just overzealous logging which can be ignored.

It was fixed/removed along with general tidyup of noisy close logging.