What makes a bean a CDI bean?

Question

In the top answer to this question for example : Java EE 6 @javax.annotation.ManagedBean vs. @javax.inject.Named vs. @javax.faces.ManagedBean I read that:

To deploy CDI beans, you must place a file called beans.xml in a META-INF folder on the classpath. Once you do this, then every bean in the package becomes a CDI bean.

And also it is said that:

If you want to use the CDI bean from a JSF page, you can give it a name using the javax.inject.Named annotation.

I have a sample code that goes like this:

@ManagedBean
@ViewScoped
public class SignUpPage {

    private User user;

    @PostConstruct
    public void init() {
        user = new User();
    }

    @Inject
    private UserDao userDao;
// rest of the class

So as far as I understand, my bean is still a JSF Managed Bean, it is not a CDI bean(or is it?). By the way, I have a beans.xml in my WEB-INF folder.

And @Inject works just fine in here. Also, I can access the bean with EL just fine(which makes me think it is still a JSF Managed Bean)

The UserDao class looks something like this:

@Stateless
public class UserDao {
    EntityManager em;
    @PostConstruct
    public void initialize(){
        EntityManagerFactory emf = Persistence.createEntityManagerFactory("Persistence");
        em = emf.createEntityManager();
    }

So, it is as far as I know an EJB..

So do I have any CDI beans in this example? How does @Inject work here?

Hope my question is clear, Regards!

Petr Mensik · Accepted Answer · 2013-09-02T20:05:57.177

2

By CDI specification, every JavaBean is a Managed Bean (do not confuse it with JSF @ManagedBean, this is a different one) in project where the beans.xml is present. So every class is also eligible for dependency injection. Note that default scope of this class is Dependent.

edited Sep 02 '13 at 20:05

answered Sep 02 '13 at 19:58

Petr Mensik

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So for example the Dao class here is an EJB + a CDI bean. And SignUpPage is a JSF Managed Bean + a CDI bean? – Koray Tugay Sep 02 '13 at 20:01
yes, but is a really bad practise to mix up CDI with JSF, you can get unexpected results. So make use `@Named` instead of `@ManagedBean` and make sure that your scopes are from the package `javax.enterprise.context.*` – Petr Mensik Sep 02 '13 at 20:05
How about mixing CDI with EJB? If I change the SignUpPage to a CDI bean only ( with Named and from that package you mention ), is it ok to use Inject annotation? If I use the EJB annotation, is it ok as well? – Koray Tugay Sep 02 '13 at 20:08
You can have even have CDI, EJB and JSF bean in once:-)And for the first question - yes, you can use `@Inject` for EJB beans, it's even a good practise. You only need `@EJB` if you are injection remote EJBs – Petr Mensik Sep 02 '13 at 20:12
Interesting, thanks I had no idea. So I can have a Statless ManagedBean which is Sessionscoped? That is confusing.. – Koray Tugay Sep 02 '13 at 20:14
I suppose you can but it really doesn't make sense. So you really need to mix up CDI and EJB reasonably:) – Petr Mensik Sep 05 '13 at 21:56

What makes a bean a CDI bean?

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