Why is PostConstruct not called?

Question

I am working on a simple Java EE application.

I have class like this:

import javax.annotation.PostConstruct; import javax.ejb.Stateless; import javax.persistence.EntityManager; import javax.persistence.EntityManagerFactory; import javax.persistence.Persistence;  @Stateless public class BlogEntryDao {      EntityManager em;      @PostConstruct     public void initialize(){         EntityManagerFactory emf = Persistence.createEntityManagerFactory("Persistence");         em = emf.createEntityManager();     }      public void addNewEntry(){         Blogentry blogentry = new Blogentry();          blogentry.setTitle("Test");         blogentry.setContent("asdfasfas");          em.persist(blogentry);      } } 

So my managed bean calls this method. Until here no problems. But since the initialize method is not called, I am getting an NPE in em.persist.

Why is the initialize method not being called? I am running this on Glassfish server.

Regards.

Answer 1

The Java EE bean annotations such as @PostConstruct only apply to container-managed beans. If you are simply calling new BlogEntryDao yourself, the container isn't going to intercept the creation and call the @PostConstruct method.

(Furthermore, you'd be better off using @PersistenceContext or @PersistenceUnit instead of manually fetching the EntityManagerFactory in your initialize() method, and you should be creating an EntityManager for each call to addNewEntry(), since they're short-lived. Making these changes would eliminate the need for initialize() at all.)