Sounds like a case of creating connections without closing them.
Sad to see this problem still exists with newer versions... We have suffered this problem and have allowed our project manager to dedicated several developers to solving this... We went through our system and cleaned up our jdbc code to make sure we closed our resources and connections before exiting a method.
But we still see this issue... I'm beginning to loose some faith in this app server since my company focuses on medical products and we simply can't have problems like this. We moved from Websphere to this app server about 2 years ago but may have to look for something a bit more stable again.
Has anyone attempted to fix this issue outside of the jboss team. I would be interested.
Just a side note: Spring has a great library dealing with JDBC/ORM, avoiding any resource leakage.
This has nothing to do with JBoss, but could help you in the future.
I would also like to point out that we I am also becoming somewhat skeptical about JBoss.