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List all the packages in Java which contain the 'Wrapper Class' for example java.lang. Does java.util contain the Wrapper class?

Vedansh Agrawal
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1 Answers1

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They are in java.lang.

The wrappers is Byte, Short, Integer, Long, Float, Double, Character and Boolean.

Integer i = new Integer(26);
int j = i.intValue(); // 26

EDIT 1: There are no wrappers in java.util.

EDIT 2: All number wrappers extends Number.

EDIT 3: There are Optional in java.util. In Java 8+, it uses generic Optional.

EDIT 4: Optional is'nt a primitive wrapper

JustAProGamerAndDeveloper
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  • `There are no wrappers in java.util.` what about `Optional` or `Date`? – Piro Mar 24 '18 at 05:53
  • Yeah, Optional is, but Date? – JustAProGamerAndDeveloper Mar 24 '18 at 05:55
  • @Piro So you mean `Optional` and `Date` are wrapper classes? – Aniket Sahrawat Mar 24 '18 at 06:42
  • @AniketSahrawat I edited and `Optional` is but not `Date` – JustAProGamerAndDeveloper Mar 24 '18 at 06:55
  • @AniketSahrawat that depends on definition of wrapper. `Date` is wrapper for `long` adding methods to work with long as representation of date – Piro Mar 24 '18 at 07:08
  • @Piro If you consider `Date` as a wrapper class just because it contains `long` field then every class packaged with ME, SE, EE, etc will be considered as a wrapper class. The wrapper classes are those packaged inside `java.lang` and are called primitive wrapper classes. – Aniket Sahrawat Mar 24 '18 at 11:25
  • @AniketSahrawat as I said, it depends on definition. You did not said you want Boxing classes for primitive types. – Piro Mar 24 '18 at 11:36
  • @Piro No! The definition of wrapper class is only one: *primitive wrapper class*. If you consider `Date` as a wrapper class then ***every class packaged with ME, SE, EE, etc will be considered as a wrapper class*** – Aniket Sahrawat Mar 24 '18 at 11:37
  • @AniketSahrawat then Option is also not valid. What about [AtomicInteger](https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/atomic/AtomicInteger.html)? – Piro Mar 24 '18 at 11:39
  • @Piro even AtomicInteger is not considered as primitive wrapper class. – Aniket Sahrawat Mar 24 '18 at 11:41
  • @AniketSahrawat I somehow mistook you with OP. [This is what I expect as wrapper class](https://stackoverflow.com/questions/889160/what-is-a-wrapper-class) – Piro Mar 25 '18 at 03:30