Glassfish doesn't bring up EntityManager if DAO is not Stateless - jpa

Question

I have an EAR application with an EJB module, that contains one persistence unit and many EJBs (as service and DAO layer).
#Stateless
public class BranchDAO {
#PersistenceContext
private EntityManager entityManager;
}
But DAOs as Stateless beans are not recommended. So I create this annotation using CDI:
#Dependent
#Stereotype
#Target(ElementType.TYPE)
#Retention(RetentionPolicy.RUNTIME)
public #interface DAO {
}
After my DAO is changed to not use #Stateless:
#DAO
public class BranchDAO {
#PersistenceContext
private EntityManager entityManager;
}
But the Glassfish doesn't bring up the entity manager when the application starts. And when I call the DAO, the entity manager is in an illegal state.
java.lang.IllegalStateException: Unable to retrieve EntityManagerFactory for unitName null
This error only occurs in Glassfish 3, but not in JBoss AS 6. Using JBoss AS 6 I can see the Hibernate logs in startup (but I don't see them with Glassfish).
As a temporary solution I created an Stateless bean with the content below. It's not beautiful solution, but works fine in Glassfish.
#Stateless
#Startup
public class AutoStartEntityManager {
#PersistenceContext
private EntityManager entityManager;
}
So, how I can force Glassfish to bring up EntityManager when I'm not using #Stateless in my DAO?

Answer 1

Try specifying explicitly the unitName:
#PersistenceContext(unitName="yourJPAUnitName")
private EntityManager manager;
(A sidenote - are you sure you need the DAO in dependent scope? Shouldn't it be singleton?)