I am new in JPA and I can't understand the use and the difference between stateless and stateful.
Any experiences?
regards, Haythem
Stateless and Stateful are EJB Session Bean concept, not of JPA.
Nota bene: JPA is part of EJB specification, but can be used separately and outside of an EJB container. This is what usually causes the confusion.
Edited: A useful SO thread, Why Use Stateful Session Beans.