Did anyone actually get this working? I'm getting the oh-so-(not)-helpful error message: Exception creating EntityManagerFactory using PersistenceProvider class org.hibernate.ejb.HibernatePersistence for persistence unit myDatabase. My app works great on Tomcat, but gives me this error when I try to deploy it on OC4J using their admin web-front-end. I was at least able to get OC4J working with MySQL (by adding the driver jar to the correct directory, adding the information to data-sources.xml, restarting the server, and testing it successfully via the front end), which got me past the "adaptor cannot connect to database" error. I'm currently using JBoss's EJB3 implementation...is it necessary to use Oracle's? If so, how do I go about configuring my app to use it? --Rich View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4025859#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...