Namik

public class A {
   private Object b;

   public Object getB() {
      return b;
   }
}

public class A1 extends A {

}

public class A2 extends A {
}

public int calc(String data, A value, Boolean rez) {
 value.getB();
}

public interface I {
   Object getC();
}

public class B implements I {
   private Object c;

   public Object getC() {
      return c;
   }
}

public class D implements I {
   private Object c;

   public Object getC() {
      return c;
   }
}

public int calc(String data, I value, Boolean rez) {
 value.getC();
}