i am learning Java Persistence API with Annotations and the Hibernate Entity Manager. My learning path objective is to implement and deploy a application in a JBoss cluster.

Im writing a tutorial (and learning at the same time) for my website about this and all worked fine (DDL generation, annotations). For keeping it simple i'm trying to implement a Factory Method Pattern to get the DAO's.

For example, its common to implement the DAO pattern (with Factory and/or related patterns) but since the JPA provides a standard API, is it really needed since we can specify the persistence provider? Or should the JPA be an implementation of a DAO Factory?

If anyone is using JPA for database access (without EJB), how are you implementing the data acess and business logic architecture?