Regarding Output Of The Code

[V. Potluri]

Hi,

I would be thankful if anyone explain why "ob3 is equal to ob4" is not part of output?

 

       Integer ob1 = 100;
       Integer ob2 = 100;
       Integer ob3 = 1000;
       Integer ob4 = 1000;
       
       if(ob1 == ob2)

    	   System.out.println("ob1 is equal to ob2");

       if(ob3 == ob4)

    	   System.out.println("ob3 is equal to ob4"); // Why this is not part of Output.

Thanks In Advance,
Gopal

[vysh srini]

== is used to compare only primitives. Use equals() method to compare wrapper classes and objects. For your code

if(ob3.equals(ob4))

will result in both the Integers to be true

[vuthlarhi donald]

The reason is because the Interger is cashed from -128 to 127, anything that's not in that range the result is not guaranteed.
what do I mean when I say it is cashed.
if you have Interger i =20; and Integer j =20, i and j refers to the same, but if you go like Interger i =128 and Interger j =128, two objects are created in the heap, just like when you go like String s = new String("Don"); and String k =new String("Don"), so when you use the == to refers to these integers it will say..no they are not equal