Deadlock resolution.

Whenever you hit a web server / app server hang problem because of an hosted web application, you can try the following:

1. Take a thread dump of the process. You can issue "kill -3 pid". The thread dump will be available in the web server errors log file.

2. Most of the threads will be waiting to acquire a lock on particular resource say R1. There will be one thread who had acquired the lock on R1 and probably in the following state.
Doing an indefinite wait on trying to acquire a lock on another resource R2. This lock on R2 could be with another thread that is in the wait queue trying to acquire R1 (OR) R2 will never be available because of resource starvation.

3. All threads have entered into lock.wait() and no notify call to wake up these guys.