Why does 1 != 1 return true?

Question

if (responseEntity.getBody().getMeta().getCode() != ApiExceptionEnum.SUCCESS.code()) {
    return null;
}

code like this,

responseEntity.getBody().getMeta().getCode() -> Integer  1
ApiExceptionEnum.SUCCESS.code() -> Integer 1

sometimes it will return null !!

why ?

the response is from redis

For the same reason that `new Integer(1) == Integer.valueOf(1)` is `false`. — T.J. Crowder, Dec 18 '17 at 11:33
thank you , finally i use Integer.intValue , but why when Integer = 1, such code ,` Integer != Integer` return true ? — Jason Yu, Dec 18 '17 at 11:34
in java when Integer little then 128 1= 1 return true , when Interger bigger then 128 1= 1 return false ,but I got the situation 1 != 1 return true — Jason Yu, Dec 18 '17 at 11:40

score 0 · Answer 1 · answered Dec 18 '17 at 11:43

0

In this case == or != checks whether compared objects are pointing to the same place in memory. To compare values stored in compared objects, use .equals() method inherited by all Java objects from Object class.

answered Dec 18 '17 at 11:43

Przemysław Moskal

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when the Interger is 1 , why it doesn't aotuunboxing? – Jason Yu Dec 18 '17 at 11:50
@JasonYu Because equals() method is inherited by objects, primitive types are not considered as objects in Java and they aren't inheriting anything. If you call this method it means that you want to compare objects, not primitive types – Przemysław Moskal Dec 18 '17 at 12:02

Why does 1 != 1 return true?

1 Answers1