Why method overriding is required?

Question

1. As if you extend the class and override the method then what will be the difference between new method and overridden method, except same name and method signature .

2. In the below code class A has some method parentMethod() and the same is overridden in class B by extending class A.

I want to know what is the difference between overridden method and a new method except the name and why we need to go for overridden method with classes.

class A {
    void parentMethod(){
       //some code
    }
}

class B extends A {
    void parentMethod() { //overridden method
        //some overridden code
    }
    void childMethod() {//new method
        //some new code
    }
}

Answer 1

Overriding is used when you have two classes with very similar code. Some of the code is different so you want to have some common code and some abstract methods that can be changed from variation to variation. The variations will turn into abstract classes that extend your base class. Read more here https://docs.oracle.com/javase/tutorial/java/IandI/abstract.html.

Answer 2

Override method use with example is explained below.

You can use it where you want to use the same "method name" and "signature" but need to give new code functionality.

Check the below code where,

1. class "Car" is there.
2. created default method for car as "myHorn()".
3. created new class as "Ferrari".
4. overriden the method "myHorn(), as for car i want to use new horn.
5. now for all cars you can create override the "myHorn()" method and customize code.

Class Car{
//parent class method having default horn
void myHorn(){
System.out.println("peeee..peeeee.peee");
}
}

class Ferrari extends Car{
//overridden method using same method and overriding horn
void myHorn(){
System.out.println("fuuuuuuuuuuu..fuuuuuuuuuu");
}
}

class Swift extends Car{
//Creating object of Swift class and calling  method of Class "'Car"
Swift car = new Swift();
//if want to use default horn
car.myHorn();
}
}