Your fork 40,000 times will run in one transaction unless you make the subprocess run asynchronously. Thus, I would imagine that your transaction is timing out to cause this exception... as 40000 processes would take a lot of time to spin up. When the transaction times out, the next would say, wait there is no transaction active! B View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4226074#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...