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Method Overloading in Java





Method Overloading is creating a method with the same name as an existing method in a class. Hence in simple words, method overloading allows us to have multiple versions of a method within a class.




Why method overloading is used?


Method overloading is mainly used in a situation when we want to create multiple specialized versions of a method in a class, with each version having the same name and doing some specific specialized task.




How method overloading is achieved?







    Rules to method overloading -



  1. Overloaded methods MUST have different arguments.

  2. This is the most important rule to perform method overloading. In order to create multiple versions of a method, each version of this method MUST have a different type of arguments.

    //Java - Example of method overloading
    
    class Math
    {
    public void add(int a, int b)		//add method adding two integers
    {
    	System.out.println(a+b);
    }
    
    
    public void add(float a, float b)	//add method adding two floats
    {
    	System.out.println(a+b);
    }
    }
    
    class Overload
    {
    public static void main(String... ar)
    {
    	Math ob = new Math();
    	ob.add(1,2);
    	ob.add(2.5f,4.5f);
    }
    }
    
    

    Output -

    3
    7.0
    • We have overloaded an add() method and have created its two different versions within its Math class.
    • One version of the add() method is adding two integers.
    • While the second version of the add() method is adding two floating-point numbers.




  3. Overloaded methods may/may not have different return types.

  4. In the previous coding example, you have seen the overloaded add() methods which were having a similar, void return type. In this example, we will overload the add() method with different return types.

    //Java - Example of method overloading
    //A Math class with overloaded add methods, having different return types
    
    
    class Math
    {
    
    public int add(int a, int b)
    {
    	return(a+b);
    }
    
    
    public float add(float a, float b)
    {
    	return(a+b);
    }
    
    }
    
    class Overload
    {
    public static void main(String... ar)
    {
    	Math ob = new Math();
    	System.out.println(ob.add(1,2));
    	System.out.println(ob.add(2.5f,4.5f));
    }
    }
    


    Output -


    3
    7.0





  5. Overloaded methods may/may not have different access modifiers.

  6. In the previous coding example, you have seen the overloaded add() methods having a similar, public access modifier. In this example, we will overload an eat() method of a Rabbit class with each overloaded version specified with a different access modifier.

    //Java - Example of method overloading
    
    class Rabbit
    {
    protected void eat() 	     //eat method with protected access modifier
    {
    	System.out.println("Rabbit eats carrots");
    }
    
    public void eat(String st)   //eat method with public access modifier
    {
    	System.out.println("Rabbit eats "+ st);
    }
    }
    
    class Overload
    {
    public static void main(String... ar)
    {
    	Rabbit ob= new Rabbit();
    	ob.eat();
    	ob.eat("grass");
    }
    }
    


    Output -


    
    Rabbit eats carrots
    Rabbit eats grass




  7. Overloaded methods may/may not declare new or broader checked/unchecked exceptions.

  8. Different versions of a method achieved by method overloading may/may not throw some new or broader checked/unchecked Exceptions and it's not an issue.

    //Java - Example of method overloading
    
    class A
    {
    public void greet() throws Exception
    {
    	System.out.println("Hello!");
    }
    
    public void greet(String st)
    {
    	System.out.println("Hello from " + st);
    }
    }

    • In this code, class A has two versions of method greet(), hence it is overloaded.
    • One version of the method throws a checked exception, Exception.
    • While the other version of the method doesn't throw any exception at all.



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Overloading through inheritance


In all the previous coding examples we saw how to create multiple versions of a method within the same class but now we will see how to create multiple versions of a method which is inherited by a class(subclass) from another class(superclass).

//Java - Example of method overloading through inheritance
 
class Sports			//superclass
{
public void play()		//original play() method with no arguments
{
	System.out.println("Play any sport");
}
}

class Tennis extends Sports	//subclass
{
public void play(String name)	//overloaded play() method with String arguments
{
	System.out.println("Play "+ name);
}
}

class Overload 
{
public static void main(String... ar)
{
	Tennis ob= new Tennis ();
	ob.play();
	ob.play("Tennis");
}
}


Output -


Play any sport
Play Tennis


Program Analysis






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