We are running a hudson master on glassfish v 2.1. After some time of operation
connecting to the web interface hangs indefinitely. At that point in time, it
appears as though hudson still is running as we see jobs are getting executed in
the logs and even mails being sent.

Checking with jconsole for deadlocked threads we don't see any. Also swap usage
is negligble and in particular the java process shows normal memory usage. Also,
the CPU load on the master is low.

Restarting the glassfish application server solves the problem and the web
interface is available again.