Example of Method Overriding

public class polymorphism {
public static void main(String[] args) {
base obj;
  obj= new base();
obj.display();
obj = new derived();
obj.display();
}
}
class base
{
void display()
{
System.out.println("Base Class");
}
}
class derived extends base
{
void display()
{
System.out.println("Derived Class");
}
}

//**********************************************************************
output:-

Base Class
Derived Class


Explanation: IN above example , void display() is the same name method used in base class and derived class but while calling these methods from main,
one reference variable is created
base obj;

here obj is a reference variable

obj = new derived();
here we have created object of derived class and then
obj.display();
will call the display method from derived class.

and same way we have created object for base class,
obj  = new base();
hence it will call display method of base class
obj.display();