Why do we overload a constructor?

We overload constructors to give options on how to initialize an object.

Public Person()

{

name=""

age=""

gender=""

}

...if you override

Public Person(String name, int age, String gender)

{

this.name=name

this.age=age

this.gender=gender

}

Now upon coding time, if you need to initialize it with parameters you have two choices:

1. When an object will be initialized and you don't have to pass values to the parameter, use the constructor without parameters,
2. and if you need to pass parameters, then use the one with parameters.

Now if you ask me what's the use?

well, since you are creating a class, you are encapsulating. you want as much to limit the use of your internal properties.

e.g.

private name

private birthyear

public Person(String name, Int age)

{

this.name=name

this.birthyear= yearNow-age

}

public Person(String name, Int birthdate)

{

this.name=name

this.birthdate=birthdate

}

You make sure that everytime a Person() is initialized, birthday property has a value either from age or birthdate.

I know the example is absurd but there are lots of complex example for this, I do overloading of constructors most of the time. from creating connection objects, to creating business process objects, since they differ in their needs.

Problem that often occur is code duplication. It's up to you to make a way to minimize/avoid duplication of code. usually I do this

public Person(String name, Int age)

{

Person(name, yearNow-age)

}

public Person(String name, Int birthyear)

{

this.name=name

this.birthyear=birthyear

Person();

}

Hope this gives an idea.