Hi, I think there is an error in the code generated by NetBeans to use an EntityManager.
I create a session Beans stateless. In this session bean, Alt-Insert > Use Entity Manager... The inserted code use UserTransaction when the bean is not annotated with @TransactionManagement( TransactionManagementType.BEAN): @PersistenceContext(unitName = "samplePU") private EntityManager em; @Resource private javax.transaction.UserTransaction utx; public void persist(Object object) { try { utx.begin(); em.persist(object); utx.commit(); } catch (Exception e) { Logger.getLogger(getClass().getName()).log(Level.SEVERE, "exception caught", e); throw new RuntimeException(e); } } Normally the transaction should be managed by the container without using UserTransaction. Richard