Question

I’ve got a NullPointerException using EJB3 in a J2SE environment (without EJB3 container)

Briefly, I’ve got a stateless bean implementing an interface.
When I call it in another class like in a main, a NullPointerException is triggered.

Sample:

@stateless
@Local(IMyInterface.class)
public class myBean implements IMyInterface{...}

public class Main{
   @EJB
   IMyInterface myInterface;

   public static void main(String[] args){
      Result result = myInterface.myBeanMethod(); // Exception happens here
   }
}

I guess I miss some initialization stuff because the EJB is null when I first try to use it…

Thanks for your help,

Answer 1

While you can use JPA (which is part of EJB 3) “Entity Beans” (actually, POJOs) in a J2SE environment, you can’t use Session Beans without a container and you can’t benefit from injection of resources using the @Resource or the more specialized @EJB and @WebServiceRef annotations in a non-managed environment, i.e. a container. In other words, only managed components support injection (Servlets, JSF Managed beans, EJB components, etc).

So, in your case, you’ll need to:

1. Deploy your Session Bean in a Java EE container (like JBoss, GlassFish, WebLogic, etc)

2. Lookup the remote EJB using explicitly its global JNDI name. The code will look like that:

   Foo foo = (Foo) new InitialContext().lookup("FooEJB");
   

A few additional remarks:

• With EJB 3.0, the global JNDI name is container dependent so I can’t tell you what it will be exactly (EJB 3.1 finally introduced “portable global JNDI names“).
• You’ll need to set up the JNDI environment (which is container dependent) for the lookup either by providing a jndi.properties on the class path or by using the InitialContext(Hashtable) constructor.
• You’ll need to provide the application server “client library” on the class path of the client (which is obviously specific to each product).

Search for previous questions or open a new one if you need more specific guidance.