Whats the main difference between a Collection of String (Collection)and a simple, plain collection?
+6
A:
A plain Collection will accept any kind of Object, while a Collection<String> will only accept Strings.
If instead of String you had a Collection of something that could be extended, say Collection<List>, then the collection would accept anything that is a subtype of List. Sun's Java Tutorial on Generics is a good place to go to learn more.
Bill the Lizard
2010-07-07 11:32:32
please add "<String>" in the second part of your sentence...
Koen
2010-07-07 11:33:55
@Koen: Thanks. I forgot that the WMD parser cancels those out unless you put it in code spans.
Bill the Lizard
2010-07-07 11:36:38
Thanks for the notification. I thought that same first when I saw my post and then realised the obvious.
Global Dictator
2010-07-07 12:03:57
+3
A:
Once compiled, nothing... But it can help you not to try to put any other object than a String while coding, and you don't have to cast back the objects that you retrieve from the collection.
Vinze
2010-07-07 11:34:44
A:
Generics. using a Collection as an argument or as a return type ensures that the caller/accessor to anticipate the objects to be present in the collection. this helps to avoid unnecessary casting to String.
Type erasure ensures that the generic definition is removed at runtime.A feature which helps in backward compalitibility.
frictionlesspulley
2010-07-07 13:05:37