public class A {    private D d;    private C c;    public A (C c) {        this.c = c;    }    public void setD (D d) {        this.d = d;    }    ...        public interface B {        public void aa();        public void bb();        public void cc();    }}

public class C {    private A a = null;    ...        protected void init() {        a = new A(this);        a.setD(new D());    }        protected class D implements A.B {        public void aa() {            ...        }        public void bb() {            ...        }        public void cc() {            ...        }    }}