Overloading overridden method am I overloading parent or sub-class method

Question

Overloading overridden method in subclass, am I overloading parent method or sub-classes method?

I understand generally what overloading and overriding is.

Overloading - same method different parameters and maybe return type in the same class.

Overriding - in subclass same method signature as in parent but different implementation.

class A {
    public void a() {
        System.out.println("A.a");
    }
}

class B extends A {
    public void a() {
        super.a();
        System.out.println("B.a");
    }

    public void a(int x) {

    }
}

Is method B.a(int x) overloading A.a or B.a?

Answer 1

You override something that is inherited, so B.a() overrides A.a(). Overriding means to redefine.

Overloading is when your class have more than one definition of the same method name (each with different argument types). In B, the name a is overloaded. There is B.a() and B.a(int x).

Some of the definitions might be inherited. So if you remove B.a(), the class B would still have a method a() since it inherits it from A. And the method name a would still be overloaded in B.

Answer 2

Method B.a(int x) overloads B.a(), since method overloading resolution takes place at compile time, and depends on the compile time type of the variable for which you are calling the method.

On the other hand, the decision of which overridden method to execute takes place at runtime, and depends on the run-time type of the instance for which you are calling the method.

You can see that by trying the following code, which won't pass compilation, since class A has no method of the signature a(int x):

A b = new B ();
b.a(4);