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.)