- Polymorphism in java is a concept by which we can perform a single action by different ways.
- Polymorphism is the ability of an object to take on many forms.
- There are two types of polymorphism in java
- Compile time polymorphism (Static)
- Runtime polymorphism (Dynamic)
- We can perform polymorphism in java
- Method overloading
- Method overriding.
Method Overloading:
If a class has multiple methods by same name but different parameters, it is called as Method Overloading.
Example of method overloading
class DemoCal
{
void sum (int a,int b)
{
System.out.println (a+b);
}
void sum (int a, int b, int c)
{
System.out.println (a+b+c);
}
 
public static void main(String args[])
{
DemoCal a=new DemoCal ();
a.sum (10, 10, 10);
a.sum (20, 20);
}
Output:30 40
Method Overriding:
If subclass (child class) has the same method as declared in the parent class, it is known as method overriding in java.
Example:
class Bank
{
int getRateOfInterest(){return 0;}
}
class SBI extends Bank
{
int getRateOfInterest(){return 8;}
}
class ICICI extends Bank
{
int getRateOfInterest(){return 7;}
}
class AXIS extends Bank
{
int getRateOfInterest(){return 9;}
}
class Test2
{
public static void main(String args[])
{
SBI s=new SBI ();
ICICI i=new ICICI();
AXIS a=new AXIS();
System.out.println ("SBI Rate of Interest: "+s.getRateOfInterest ());
System.out.println ("ICICI Rate of Interest: "+i.getRateOfInterest ());
System.out.println ("AXIS Rate of Interest: "+a.getRateOfInterest ());
}
}
Output:
SBI Rate of Interest: 8
ICICI Rate of Interest: 7
AXIS Rate of Interest: 9