The XA spec has this to say on the matter: "An RM can mark a transaction branch as rollback-only any time except after a successful prepare. A TM detects this when the RM returns a rollback-only return code. An RM can also unilaterally roll back and forget a branch any time except after a successful prepare. A TM detects this when a subsequent call indicates that the RM does not recognise the XID. The former technique gives the TM more information. So your options are: keep some meta data around after the timeout, so that you can reply 'rollback only', or throw away everything and reply 'unknown tx id'. It's up to the tm to deal with either of those cases. I don't off the top of my head know how well JBossTS will respond to either of them. I'm not aware of any major RM that uses either, so I suspect we'll run into seldom exercised corner cases. BTW, what's the perceived advantage to you in implementing timeouts at the resource level, given that users will (hopefully) set an overall tx timeout interval if they want one? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4186357#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...