Do your server freeze after many reload/redeploy of your webapp ?

Try to change the PermSize of your server to: -XX:PermSize=256m -XX:MaxPermSize=256m

More about the permanent generation:

• "How should the permanent generation be sized?"
• A better explanation can be found in jboss documention
• A pragmatic explanation - http://www.unixville.com/~moazam/stories/2004/05/17/maxpermsizeAndHowItRelatesToTheOverallHeap.html

You can also see my post on the Hibernate Forum