Oh dear..dear... Ok, first thing is that I am using Eclipse Ganymede. I must be doing someting terribly wrong here. So far as I have understood, I have "physically" copied all those hibernate jar files from their respective setup folders to the jboss server default lib. Not so long ago I was unable to deploy my EJB3 JPA entity program because I was not using the Hibernate compatibility matrix to ensure correct versions. I copied all the appropriate hibernate jars (hibernate-distribution.3.3.jar, hibernate-common-annotations.3.4.jar, hibernate-annotations.3.4.jar, hibernate-entitymanager.jar and hibernate-validator.3.4.jar to the jboss server default lib and everything works. Also I must add that the ear files are also saved in the jboss server default deploy and sar and esb files are also saved here. I usually get confused by the Eclipse Package Explorer structure within the IDE and Windows Explorer as they have similar file structure (the same when it comes to the java projects). All I know is that when you get the hibernate distributions.zip (or gz.tar) or the hibernate entity manager and annotation zip or tar files, they will expand by default to their own folder with the same name as the product (e.g. C:\hibernate-entitymanager.3.4.0). Within these you can find the core jar file you need and any accompanying jars in the lib sub-folder. I just copy them all physically in Windows Explorer to jboss.4.2.2.GA\server\default\lib. Is this the right way to do it ? Or do I copy it into the clipse Package Explorer lib folder ? If so, where physically in the Windows file system will these files be kept ? Many thks for your assistance. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4228563#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...