Difference Between Method Overloading and Method Overriding?

MethodOverloading

Same method name and different parameters is called method overloading

It may contain same method name and same parameters with different data types and order(number of arguments)

It occurs in same class.

It provides fast execution than overriding

It may or may not require inheritance

Static method can be overloaded

Example: compile time polymorphism

class Cal

{

    void add(int a, int b)

    {

         System.out.println("sum of two number:"+(a+b));

    }

    void  add(int a, int b, int c) 

    {

          System.out.println("sum of three number:"+(a+b+c));

    }

}

public class LearningPoint92

{

   public static void main(String args[])

   {

                Cal c1 = new  Cal();

                 c1.add(50, 20);

                 c1.add(50, 20, 30);

              }

        }

OUTPUT:

sum of two number:70

sum of three number:100

Method overriding

Same method name and same parameter is called method overriding

It may contain same method name and same parameters with same data types,return type and order(number of arguments)

It occurs in different class.

It provides slow execution than overloading

It  require inheritance

Static method cannot be overridden

Example: runtime polymorphism

.class A{

   public void show(){

            System.out.println("Hello");

   }

}

public class B extends A{

        public void show(){

         super.show();   //to call superclass method

            System.out.println(" Welcome To LearningPoint92");

   }

   public static void main(String args[]){

            B a1=new  B();

            //A a1 = new B();

            a1.show();

      }

     }

OUTPUT:

 Hello

Welcome To LearningPoint92

Note:

upcasting is required in runtime polymorphism. Super class reference refer to subclass object is called upcasting.you can call subclass method using upcasting

A a1 = new B();

Where  A  a1=superclass reference

Where new B () =subclass reference