Exact need of Method Overloading in Java [duplicate]

Question

Since I have found so many examples and conclusions about Method Overloading but still I am confusing in real time how we are using it.

First of all method overloading is a class level activity means within that class we are overloading a method with same name but different arguments like

void sum(int a,int b){System.out.println(a+b);}  
void sum(double a,double b){System.out.println(a+b);} 

and after we are calling this method like

public static void main(String args[]){  
ClassName obj=new ClassName ();  
obj.sum(10.5,10.5);  
obj.sum(20,20);  
}  

Suppose instead of this I will take two separate method like

void method1(int a,int b){System.out.println(a+b);}  
void method2(double a,double b){System.out.println(a+b);} 

And I will call this 2 methods same as above

public static void main(String args[]){  
ClassName obj=new ClassName (); 
obj.method1(20,20);   
obj.method2(10.5,10.5);  
} 

In both the case for both the methods the activities are same then what is the exact need of overloading/polymorphism in this case.

Somewhere I found that Method overloading increases the readability of the program can anybody please specify that only because of this line we are using method overloading.

Thanks.

Answer 1

Suppose we didn't have method overloading in Java.

Instead of :

System.out.println("String");
System.out.println(5);
System.out.println('c');
...

we would have :

System.out.printlnString("String");
System.out.printlnInt(5);
System.out.printlnChar('c');
...

or even worse :

System.out.println1("String");
System.out.println2(5);
System.out.println3('c');
...

Both alternatives would make the code less readable.