Constructor

Constructor:

-          It is a specialized method od a  class which is invoked when an object is created for the class.

-          The difference occurs in the following areas:

o    Name

o    Return Type

o    Type of Calling

o    Time of Calling

o    Frequency of Calling

o    Purpose

Name:

                Constructor Name and Class Name should be same.

                Ex:                   

     

Return Type:

                Constructor name shouldn't have any return type.

Type of Calling:

                Constructor is called as soon as object is created. It is the first method called by the Object.            

Time of Calling:

                A Constructor is Called Implicitly.

Frequency of Calling:

A constructor will be called when the object of the respective class is created and also when the objects of the derived class are created.

Purpose:

The Main purpose of the constructor is, It carries the code which need to executed as soon as object is created.

               

There are 2 types of constructors:

a)       Parameterized constructor.

b)      Un-parameterized constructor/ Zero argument constructor/ Default/ Block

Ex:

          With in the class if there are more than one constructor, then it is called as ‘Constructor Overloading’

-          In this case, by default Jcompiler calls EMP() i.e default constructor. If you want to call the parameterized constructor first, pass parameters while Object declaration.

-          One constructor of a class can call another constructor of the same class. This is called constructor chaining.