Polymorphism, Discussion on Overloading And Overriding with Examples

Polymorphism: Having many shapes, occurrence of different forms.
Overloading: Ability of a request (message / method call) to produce different results based on the request parameters.

• Overloaded methods must have same name. 
• Overloaded methods must differ in input parameters’ type or order or number
• Overloaded methods must NOT differ ONLY in their return types(i.e., having same name & input parameters).

Do overloaded methods have same method signatures ? 
No overloaded methods have not same method signatures.
Following are some examples of overloaded methods.
Example1:

package com.aurangzeb.utk;

public class OverloadedMethods {

      public void printData(int age, String name) {

      }

      public void printData(String name, int age) {

      }

      // Yes order of input parameters is different

}

     

 Example2:

package com.aurangzeb.utk;

public class OverloadedMethods {

      int addValue(int a, int b) {

            return 1;

      }

     int addValue(int a, int b, int c) {

            return 2;

      }

      // Yes numer of Input Parameters is different

}

     

 Example3:

package com.aurangzeb.utk;

public class OverloadedMethods {

      int addValue(int a, int b) {

            return b;

      }

      float addValue(float a, float b) {

            return b;

      }

   // Yes, Type of input parameters is different

}

  Example4:

package com.aurangzeb.utk;

public class OverloadedMethods {

      void printName(String fName, String lName){

           

      }

      void printName(String lName, String fName){

           

      }

      //No, same type, order and number of input parameters

}

 

Overriding:Ability of a request (message / method call) to produce different results based on the object it is sent to.

• A language feature in OOP, that allows a subclass to provide a specific implementation of a method that is already provided by one of its super-classes
• The implementation in the subclass overrides (replaces) the implementation in the super-class.(
  • Same method signature
  • Same Name
  • Same Input Parameters
  • Same Return Type
  )
• But Multiple implementations !!!