Create EJB with two interfaces. @Local interface f

I have a EAR package that contains a web module and EJB. The EJB is currently exposed its contains to local app client via Remote interface

@Stateless
public class CoreEJB implements CoreEJBRemote {

    @PersistenceContext(unitName = "CoreWeb-ejbPU")
    private EntityManager em;

    @Override
    public void packageProcess(String configFileName) throws Exception {
        //Process logics
    }

    @Override
    public <T> T create(T t) {
        em.persist(t);
        return t;
    }

    @Override
    public <T> T find(Class<T> type, Object id) {
        return em.find(type, id);
    }

    ...
}

The Remote interface is not in EAR, and look like this

@Remote
public interface CoreEJBRemote {

    public void packageProcess(java.lang.String configFileName) throws java.lang.Exception;

    public <T extends java.lang.Object> T create(T t);

    public <T extends java.lang.Object> T find(java.lang.Class<T> type, java.lang.Object id);

}

The Main of the app client is below

public class Main {
    @EJB
    private static CoreEJBRemote coreEJB;

    public static void main(String[] args) {
        coreEJB.packageProcess("path/to/a/file");
    }
}

Now i want to create an Local interface for the EJB so that in the Managed Bean of my web module, I can access the EJB via local invocation.

Do I just change CoreEJB from public class CoreEJB implements CoreEJBRemote to public class CoreEJB implements CoreEJBRemote, CoreEJBLocal and create @Local interface call CoreEJBLocal inside EJB package? Or will there be something extra? I want my Managed Bean code to be like this

@ManagedBean
@RequestScoped
public void testView{
    @EJB
    private CoreEJBLocal coreEJB;

    public void add(Something something){
        coreEJB.add(something); //Local invocation
    }
}

Do I just change CoreEJB from public class CoreEJB implements CoreEJBRemote to public class CoreEJB implements CoreEJBRemote, CoreEJBLocal and create @Local interface call CoreEJBLocal inside EJB package?

Yes, this should be sufficient. Did you try? Did it fail? Keep in mind that local interfaces are pass-by-reference and remote interfaces are pass-by-value. If callers (or the bean) mutate state on the return value (or arguments, respectively), then you're going to get different behavior between the two. You must manage this careful in your API contract.