Hi, I am trying to build an ear file with multiple jar files in the ear. I want to share one persistence unit across the jar files. I have tried putting a persistence.xml in each jar and that fails, I get an exception, javax.management.InstanceAlreadyExistsException: persistence.units:ear=ear.ear,unitName=foo already registered. After the first jar which defines the persistence unit is deployed. I have tried moving the persistence.xml up into the ear file, and it is not loaded at all. How is this typically done? View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3964705#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...