Question

I have have a class A in Java and A has some protected methods, I then have a class B which extends from A so that B can override those protected methods. I then want the ability to have a class C that extends from class B but class C should not be able to call A‘s protected methods. Is there away to do that in Java? Do I just make the parent’s class’s method’s overriden and have them final? i.g.

public class A()
{
     protected void somemethod();
     protected int somevariable;
}

public class B() extends A
{
    @Override
    final protected void somemethod();
        //How do I make some variable final or not accessible to my children?
    }

    public class C() extends B
    {
        //Now I cannot override somemethod! Is that right?
    }
}

Answer 1

No, you cannot prevent a child class from calling a parent’s protected methods. To achieve this, you would have to reduce the method’s visibility, which is not allowed. Making the method final in your class B only means it cannot be overriden in any subclasses.

The fact that you want disallow calls to protected methods for child classes appears to be a design problem to me. You might want to review how your whole class hierarchy and maybe better isolate the reponsibilites of your classes so that you don’t get into a situation where you have to prevent what would normally be allowed (calling protected methods).