Polymorphism in Java

     Polymorphism is an OOP concept that refers to the ability of a variable,function or object to take on multiple forms. Polymorphism means many forms .

Below are the 2 types which supports polymorphism in Java
1)Method Overloading
2)Method overriding

1) Method Overloading:
       Method overloading is one of the polymorphism concept which allows 2 or more methods within the same class that share the same name and the parameter for those methods are different. 

Depending on the parameter passed at the time of calling the method it will decide which method need to be called. 

Example :
To copy the code select+ctrl+C
public class OverlodedMethod { void add(int a,int b) { System.out.println("addition of two numbers "+(a+b)) ; } void add(int a,int b,int c) { System.out.println("addition of three numbers "+(a+b+c)) ; } void add(int a,int b,int c,int d) { System.out.println("addition of four numbers "+(a+b+c+d)) ; } public static void main(String[] args) { OverlodedMethod OverlodedObj =new OverlodedMethod(); OverlodedObj.add(2,6); OverlodedObj.add(2,4,6); OverlodedObj.add(2,4,6,8); } }

Output:

2) Method Overriding
 A subclass has the same method as declared in the parent class is called method overriding. Here the method name and the number of parameters are same . The implementation logic i.e the method body may change than the parent method.
Method overriding is used for runtime polymorphism. If a child class overrides the parent class method then the method in the child class will be executed else the method in the parent class will be executed.

Example:
To copy the code select+ctrl+C
class ParentClass{ void OverrideMethod() { System.out.println("Method in the parent class is executed"); } } class ChildClass1 extends ParentClass{ void OverrideMethod() { System.out.println("Method in the child class is executed from class Childclass1"); } } class ChildClass2 extends ParentClass{ } public class MethodOverride { public static void main(String[] args) { ChildClass1 Child1Obj = new ChildClass1(); ChildClass2 Child2Obj = new ChildClass2(); //Created object for childclass 2 and calling the method in the parent class Child1Obj.OverrideMethod(); Child2Obj.OverrideMethod(); System.out.println("There is no method override in Childclass2"); } }

Output: