Method Over loading in Java

 Method Overloading in Java :

 

 If a class has multiple methods having same name but different in parameters, it is known as Method Overloading

 

If we have to perform only one operation, having same name of the methods increases the readability of the  program.

If we have to perform addition of the given numbers but there can be any number of arguments, if you write the method such as a(int,int) for two parameters, and b(int,int,int) for three parameters then it may be difficult for you as well as other programmers to understand the behavior of the method because its name differs. 
 
Method overloading increases the readability of the program.
 
 
two ways to overload the method in java
  1. By changing number of arguments
  2. By changing the data type

 

1) Method Overloading: changing no. of arguments

In this example, we have created two methods, first add() method performs addition of two numbers and second add method performs addition of three numbers.


class Adder{  
    static int add(int a,int b){return a+b;}  
    static int add(int a,int b,int c){return a+b+c;}  
                    }  
class TestOverloading1{  
 
    public static void main(String[] args){  
    System.out.println(Adder.add(11,11));  
    System.out.println(Adder.add(11,11,11));  
}
 
} 


2) Method Overloading: changing data type of arguments


class Adder{  
 
    static int add(int a, int b){return a+b;}       
 
    static double add(double a, double b){return a+b;}  
                    }  
class TestOverloading2{
  
    public static void main(String[] args){  
 
    System.out.println(Adder.add(11,11));  
    System.out.println(Adder.add(12.3,12.6));  
     
}
 
}  

Method Overloading and Type Promotion

byte can be promoted to short, int, long, float or double. The short datatype can be promoted to int, long, float or double. The char datatype can be promoted to int,long,float or double and so on.
 

Example of Method Overloading with Type Promotion

class OverloadingCalculation1{  
  void sum(int a,long 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[]){  
  OverloadingCalculation1 obj=new OverloadingCalculation1();  
  obj.sum(20,20);//now second int literal will be promoted to long  
  obj.sum(20,20,20);  
  
  }  
}
 

Example of Method Overloading with Type Promotion in case of ambiguity

If there are no matching type arguments in the method, and each method promotes similar number of arguments, there will be ambiguity.

class OverloadingCalculation3{  
  void sum(int a,long b){System.out.println("a method invoked");}  
  void sum(long a,int b){System.out.println("b method invoked");}  
  
  public static void main(String args[]){  
  OverloadingCalculation3 obj=new OverloadingCalculation3();  
  obj.sum(20,20);//now ambiguity  
  }  
}

 
 
 
 
 
 

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