Could somebody explain me how global transactions work. I understand there are resource managers etc. but what I don't understand is how a transaction is able to commit or rollback all the resources involved during the process. For eg: if data is updated and then a message is sent. So if message fails then how would it rollback the data that was updated. I am assuming data would have to be committed before committing the message so at that point when the data is already committed how is it going to rollback. Also when update is called how does the data source or entity manager know not to commit the data ? I am really confused how transaction manager and resource manager interact and who controls whom. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4151837#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...