Question

Using Eclipse, how can I find which Java classes implement interface A AND interface B? Thanks.

Answer 1

I just had the same problem, and I’m really missing this feature in the Eclipse search dialog. Going through all classes manually wasn’t very pleasant, so I used this nasty workaround. Given this structure:

public interface A {
  public String x();
}
public interface B {
}

public class ImplementsBoth implements A, B {

  @Override
  public String x() {...}

}
public class ImplementsA implements A {

  @Override
  public String x() {...}

}
public class ImplementsB implements B {

}

I changed B into:

public interface B {
  public void x();
}

This results in the following error for ImplementsBoth:

The return type is incompatible with B.x()

Now it’s possible to step through all these messages in the Problems view.