Constructor In Java

Constructor is special type of method in java used to initialize the object. Constructor is invoked at the time of object creation.

Rules For Creating Java Constructor

Basically two things keep in mind when we create constructor such as :

      1)  Constructor name must be same as its class name

      2)   Constructor must have no explicit return type   

Types OF Constructor In Java

There are two types of constructor in java such as:

       1)      Default Constructor

       2)      Parameterized Constructor

Default Constructor In Java

A constructor that have no parameter(argument) is known as default constructor.

Syntax Of Default Constructor

class_name()

{

  //  Code Of Block

}

Example Of Default Constructor

class Hello

{

Hello()              // Default Constructor

{

System.out.println(“Hello World”);

}

Hello obj = new Hello();

}

Output

Hello World

Parameterized Constructor In Java

A constructor that have parameters (arguments) is known as parameterized constructor. It is used when we give different values to distinct object.

Syntax Of Parameterized Constructor

class_name(parameter1,parameter2,……….)

{

  //  Code Of Block

}

Example Of Parameterized Constructor

class Emp

{

int empid;

String name;

Emp(int I,String n)

{

empid = I;

name = n;

}

void show()

{

System.out.println(empid+“  ”+name);

}             

public static void main(String ar[])

{

Emp e = new Emp(1,“john”);

Emp e1  = new Emp(2,”david”);

e.show();

e1.show();

}

}

Output

1 john

2 david