#EJB inject does not work when you have interface inheritance - ejb

Question

I have the following code.
public interface Multiplier {
void multiply();
}
#Local
public interface MultiplierLocal extends Multiplier{
}
#Remote
public interface MultiplierRemote extends Multiplier {
}
#Stateless
public class MultiplierImpl implements MultiplierLocal,MultiplierRemote{
#Override
public void multiply() {
System.out.println(" called multiplier ");
}
}
Now when I inject this EJB like below into another ejb, it does not work. But it works when I have the Local interface type.
#Stateless
public class AdderImpl implements AdderLocal,AdderRemote {
// This does not work.
#EJB
Multiplier mul;
// This works.
/*#EJB
MultiplierLocal mul;*/
#Override
public void add() {
System.out.println(" Adder Imple called");
mul.multiply();
}
}
The error I get is in wildfly13.
Caused by:
org.jboss.as.server.deployment.DeploymentUnitProcessingException:
WFLYEJB0406: No EJB found with interface of type
'com.libin.ejb.Multiplier' for binding com.libin.ejb.AdderImpl/mul
All the EJB examples that I see does not have a base interface which is extended by local and remote interfaces. Is there a way to make this work ?

Answer 1

The idea of #Remote interfaces is to define all methods that can be invoked by a "remote client", while an #Local interface can have more methods that maybe used only inside the same application. This means that your #Local interface normally extends your #Remote interface. Hence, you inheritance hierarchy should look like this:
#Remote
public interface Multiplier {
void multiply();
}
#Local
public interface MultiplierLocal extends Multiplier{
}
#Stateless
public class MultiplierBean implements MultiplierLocal {
#Override
public void multiply() {
System.out.println(" called multiplier ");
}
}
In this case you can inject Multiplier, because it is a valid EJB interface.
Having an additional interface above the #Remote interface does not make much sense.
Additionally, you can also omit the MultiplierLocal interface, because it does not offer any value and the EJB spec says, that all public methods of a bean are automatically local. Hence, no need to specify an additional #Local interface.