"clebert.suconic(a)jboss.com" wrote : "timfox" wrote : Can you explain what the race condition is? Not so interested in the solution at this point. | | | My Post at Wed Mar 11, 2009 20:34 PM was about what' s the race. I make two calls using two different sessions, and the same XID will be used at the same time. | | That's not an explanation of the race, that's an explanation of how to reproduce the race. It doesn't explain how the race occurs. An explanation of the race would be something like: Thread a attempts to get the transaction concurrently with thread b, the is null check evaluates to false.... etc etc Anyhow, I can see why it occurs by looking at the code so no need to explain anything now. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4217433#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...