Question

What is the best use of Inheritance, other than it will reduce redundant code!
Let us take an example
Class A:Base Class
Class B:Sub Class
and Class C.

 CLASS A
    ^
    |                And     CLASS C
    |
    |
  CLASS B

i can use methods from Class A, in Class B by inheritance.
in the same i can use the methods from Class A, in Class C,
by creating instance of Class A.(say A is Public)
using inheritance, only reduce creating new Object/Instance?

Plz help me to better understand!

Answer 1

A great benefit is polymorphism. If classes B and C both inherit from A, then whenever an object of type A is required, it can be replaced by either an object of type B or an object of type C. Assuming the corresponding methods are overriden in B and C, this is very handy to get different behavior depending on which object you pass.

Example:

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

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

class C extends A {
    public void foo() { System.out.println("C"); }
}

Then:

public static void printMessage(A obj) {
    obj.foo();
}

public static void main(String[] args) {
    A b = new B();
    printMessage(b); // prints 'B'
    A c = new C();
    printMessage(c); // prints 'C'
}