ApplicationScoped and SingletonEJB

[nimo22]

I want to use a stateless singleton EJB:

Can I use this in Weld:

@Singleton
@Startup
public class MySingletonEJB {
..
}

Or should I prefer this:

@ApplicationScoped
public class MySingletonWebBean {

@PostConstruct
public void init(){
..
}
..
}

I am unsure because of the statement of Weld-Documentation:
5.4. The singleton pseudo-scope

A fourth, better solution is to instead use @ApplicationScoped, allowing the container to proxy the bean, and take care of serialization problems automatically.

However, I have thought that EJB-Container ensures to solve these problems automatically when using EJBs. Am I right?

[marcelkolsteren]

The problem is that you are comparing EJB Singletons with CDI application-scoped beans, while section 5.4 of the Weld documentation compares CDI singletons to CDI application-scoped beans.

So, in fact there are three ways of implementing a singleton:
- Use the EJB 3.1 singleton (annotation @javax.ejb.Singleton)
- Use a CDI bean in singleton pseudo scope (annotation @javax.inject.Singleton)
- Use a CDI bean in application scope

The fact that JEE6 has two Singleton concepts with the same @Singleton annotation is quite confusing. I hope that CDI and EJB will blend further in JEE7. :-)