Wrapper dual behavior

[naveen yadav]

	Integer ii = 12;
	Integer ip = 12;
	System.out.println(ip==ii);       //Line 1
  
	Integer it = 129;
	Integer ig = 129;
	System.out.println(ig==it);   //Line 2

output

Line 1 : true
Line 2 : false

Why So??

[John Stark]

Because it and ig have different values?
If you set them both to 128 then it will still be false.
If both variable have a value lower 128 and larger than -129 then they both will reference the same object for saving memory (K & B page 246 ). That is the reason for ip==ii resulting in true for a value of 12.

John

[Hebert Coelho]

Maybe because 128 is <> of 129: O.o

And yes, if pass 129 you leave the "int" zone code! [=

[naveen yadav]

Thanks john.

By the way it didn't get what herbet trying to say

Hebert Coelho
Maybe because 128 is <> of 129: O.o

And yes, if pass 129 you leave the "int" zone code! [=

can anyone simplify?

[John Stark]

I think '128 is <> of 129' means: 128 != 129. So because it = 128 and ig = 129 it == ig returns false.
'if pass 129 you leave the "int" zone code!' should probably mean leave the "byte" zone'? A variable of type byte can store values from -128 to +127 and this is the range in which two Integer objects are the same (== returns true) if their values are equal. If you move out of this zone the two Integer objects are different even if their values are the same.

John

[naveen yadav]

i get it now .


thanks john