How do we call a super class method if we already have a super class of sub class?

Question

My Question is like that if there is a child class extend by father class and which is extended by Grandfather class then how can child class directly access the Grandfather's method.

Answer 1

This is best illustrated by an example:

public class GF {
    public void one() { ... }
    public void two() { ... }
}

public class F extends GF {
    public void two() { ... }
}

public class C extends F {
    public void one() {
        super.one(); // Calls one in GF
    }

    public void two() { 
        super.two(); // Calls two in F
    }
}

The syntax for calling an overridden method from within a subclass is super.method(....). But you can only do this to call the first level overridden method. If that method is itself an override, then you cannot call the 2nd-level override; e.g. there is NO WAY for C.two() to directly call GF.two(). You can't do it reflectively, and even the JVM bytecodes won't allow it.

Answer 2

It depends on the grandfathers's method visibility. Generally it could be accessed just as a father's method. If you want to skip a parent's override of a grandfather method, you cannot do it without modifying the parent.

The only way to call grandfather's method would be like this:

public class GF {
    public void m() {
        //do something
    }
}

public class F {

    public void m() {
        //do something that you don't need in son
    }

    /* add this method for the clean access to GF*/
    public void gfM() {
        super.m();
    }
}

public class S {
    public void aMethod() {
        gfM(); //actually calls the GF.m() method
    }
}