Instance Variables

• If the value of a variable is varied from object to object such

type of variables are called instance variables

• For every object a seperate copy of instance variable will be created

• The scope of instance variables is exactly same as the scope of 

the objects. Because instance variables will be created at the time of 

objects  creation & destroy at the time of objects destruction

• Instance variables will be stored  as the part of objects

• Instance variables should be declare with  in the class directly, But outside of any

method or block or constructor

• Instance variables cannot be accessed from static area directly we can

access by using object reference. But from instance area we can access instance members directly

Ex:-

    class Test{

int x=10;

public static void main(String args[]){

Syste.out.println(x); -----------> compile time error

Test t=new Test();

System.out.println(t.x);------->10

}

public void m1(){

System.out.println(x);---------->10

}

}

• For the instance variables it is not required to perform initialization explicitly

JVM will provide default values

For Example:-

class Test{

String s;

int x;

boolean b;

public static void main (String args[]){

Test t=new Test();

System.out.println(t.s);   ---------> null

System.out.println(t.x); -----------> 0

System.out.println(t.b); --------------> false

}

}

• Instance variables also known as " Object level variables" or "attributes".