I am confused with all the three things when it comes to an implementation... I took the following path... 1) read JPA concepts 2) read EJB3 Concepts 3) developed the sample application with EJB3 & Jboss4.2.3GA....the application runs fine...even if i dont configure the Persistence Provider... 4) read the Hibernate JPA concepts....and got confused... following is the bunch of questions i am having in my mind... 1)when I am using EJB3 Entities...do i require PP...? 2)if yes...how come my application ran without configuring a Persistence Provider(PP)...? 3) can I develop an application's Persistence layer using only JPA...? 4) when I saw a sample application on Hibernate JPA...It was same as my application except a configuration of Persistence provider as Hibernate... I mean Entities(POJOs with annotations) were same...both were using javax.persistence.EntityManager for persistence operations.... so where the difference is laying between the application developed using EJB3 Entities & the one developed using Hibernate JPA....???? Thanx in advance... View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4265110#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...