This week's book giveaways are in the Refactoring and Agile forums.
We're giving away four copies each of Re-engineering Legacy Software and Docker in Action and have the authors on-line!
See this thread and this one for details.
Win a copy of Re-engineering Legacy Software this week in the Refactoring forum
or Docker in Action in the Cloud/Virtualization forum!
  • Post Reply
  • Bookmark Topic Watch Topic
  • New Topic

SCJP 5: Q on enums

 
Henry Zheng
Ranch Hand
Posts: 60
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hi all,

I have some questions regarding to enums, please shed some light

1) In the API document, the java.lang.Enum was declared as Class Enum<E extends Enum<E>>, but isn't it a recursive declaration? what does it mean then? "The type parameter should be a type extends Enum<E> in which E is itself?" -- just too complicated for me.

2) Where is the static values() method declared? I didn't find it in the Enum class, however.

Thanks

(SCJP 5 prefix added to topic title)
[ January 12, 2005: Message edited by: Barry Gaunt ]
 
Pradeep bhatt
Ranch Hand
Posts: 8927
Firefox Browser Java Spring
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Enums have 2 implictly defined methods

public static E[] values();

public static E valueOf(String name);
 
Tony Morris
Ranch Hand
Posts: 1608
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
On the topic of enums, I noticed that Enum.valueOf is documented to throw NullPointerException if enumType is null, however, an IllegalArgumentException is thrown, at least by the Sun 1.5.0 VM on win32.

I'd bother raising a bug, or checking if it already exists, if it wasn't such a mission to use the bug parade.
 
  • Post Reply
  • Bookmark Topic Watch Topic
  • New Topic