by Dinesh Thakur

Polymorphism gives us the ultimate flexibility in extensibility. The abiltiy to define more than one function with the same name is called Polymorphism. In java,c++ there are two type of polymorphism:

compile time polymorphism (overloading)

runtime polymorphism (overriding).

When you override methods, JVM determines the proper methods to call at the program’s run time, not at the compile time. Overriding occurs when a class method has the same name and signature as a method in parent class.


Overloading occurs when several methods have same names with


  • Overloading is determined at the compile time.
  • Different method signature and different number or type of parameters.
  • Same method signature but different number of parameters.
  • Same method signature and same number of parameters but of different type

Example of Overloading
     int add(int a,int b)
     float add(float a,int b)
     float add(int a ,float b)
     void add(float a)
     int add(int a)
     void add(int a)                 //error conflict with the method int add(int a)


Example: Overloading


Class BookDetails{
            String title;
            String publisher;
            float price;

setBook(String title){
setBook(String title, String publisher){
setBook(String title, String publisher,float price){



Example: Overriding


class BookDetails{
            String title;

setBook(String title){ }


class ScienceBook extends BookDetails{

            setBook(String title){}                                             //overriding

setBook(String title, String publisher,float price){ }  //overloading