public abstract class AbstractA {
 public abstract void method1(int a);
 public void method2() {
 System.out.println("method2");
 } // end method2
 public abstract void method3();
}

public abstract class AbstractB {
 public abstract void method3();
 public abstract void method4();
}

public interface InterfaceC {
 void method1(int a, int b);
 void method2();
 void method4();
}

public abstract class Choice3 extends AbstractA implements InterfaceC {
 public void method1(int a) {}
 public void method4() {}
} // end class