This keyword

This keyword:

Whenever it is required to point an object from a functionality which is under execution because of that object, then we use the ‘this’ keyword.

          The job of this keyword is only to point.It is always points to an object that is executing the block in which ‘this’ keyword is present. In a nut-shell this keyword points to the current object.

Example:

       Class A

          {

          Int  i;

          A(int  i)

          {

This.i= i+1;

          i=i+1;

          system.out.println (i);

          }

          Void function ()

          {

int i=67;

sysyem.out.println (i);

          sysyem.out.println (this. i);

          this.i= this.i+1;

}

          Public static void main (String args[])

          {

          A  a= new A( 6);

          sysyem.out.println (a.i);

a.function ();

sysyem.out.println (a.i);

//this.i=203;

}

}

Note: this operator points to address of the instance. It will never points to the context of the class.

       We know that static functions are not executed with the address of the instance even though we call then using it. that is why ‘this’ operator works only in non-static blocks. It will not work in static blocks.

·        Constructor is a non-static block, that is why we are able to use ‘this’ operator inside a constructor.

·        We can call a constructor explicitly, without creating another object of that class only through a constructor.

·        We can’t constructor through functions.

Uses of this operator:

1.    To point a constructor of a class from the constructor of the same class.

2.    To point current object from the non-static blocks .