@ApplicationScoped CDI bean and @PersistenceContext - is this safe?

Question

Is it safe to do something like this with CDI?

@Named
@ApplicationScoped
public class DAO {

   @PersistenceContext
   private EntityManager entityManager;

}
         


        

Answer 1

What about this approach:

    @RequestScoped
    class EntityManagerProducer {
    
        @PersistenceContext
        private EntityManager entityManager;
    
        @Produces
        @RequestScoped
        public EntityManager produceEntityManager() {
          return this.entityManager;
        }
    }

And in CDI Beans of any scope:

@Inject
private EntityManager entityManager;

The entity manager should be created in every single request, creating a new entity manager when it passes one CDI bean which it injects. In the injected CDI Bean, you get one entity manager which is used within the request. If a transaction is needed, the entity manager will join it. So you get a new entity manager in every request which means, everything is cleaned up at the end and you cannot get thread conflicts. Simple and easy, isn't it?