What is the need of overloading in java?

Answer 1

Overloading is very useful in Java. For instance, methods can be overload as long as the type or number of parameters (arguments) differ for each version of the method. This comes in handy when, for instance, you need to perform a complex mathematical operation, but sometimes need to do it with two numbers and sometimes three, etc.

Answer 2

The need to overload a constructor is apparent in any OO language.

Take for example the following situation.

You have written a class to represent a circle. When you declare a new circle in your code, you may or may not know how big it is.

In this case you would want two constructors.

Circle myCircle = new Circle();

Would be used if you wanted a new circle and you were going to decide at a later time how big it is.

Circle myCircle = new Circle(6.7);

Would be used if you wanted your circle to be of size 6.7 (whatever that means ;)

Another (slightly better) example:

You are writing a class to represent a person. A person always has a first and last name, but may or may not have a middle name. Because of this we would create two constructors.

(forgive my java, it's been a long time since i used it)

Person( string first, string last)

and

Person(string first, string middle, string last)

Answer 3

If you want to change the behavior of a method that exists in a super class, overloading is the only way you can alter the behavior.