Java generics on LHS but not on RHS of assignment

Question

I came across the following code and was wondering whether this is good practice:

LinkedList<String> ll = new LinkedList();

I would have written

List<String> l = new LinkedList<String> ();

So there are two questions here:

I always thought its good practice to use the type List and not ArrayList/LinkedList.
What exactly happens if you omit the diamond on the RHS of the assignment operator?

score 5 · Accepted Answer · edited May 23 '17 at 12:04

5

Always program to interfaces, that way your code stays implementation independent.
You are creating the raw type, which will give you a warning, but it will compile. "LinkedList is a raw type. References to generic type LinkedList should be parameterized". It doesn't actually matter though because of erasure.

edited May 23 '17 at 12:04

Community

answered Apr 24 '13 at 22:15

durron597

1

"It doesn't actually matter" - unless of course the constructor takes arguments of the omitted generic type(s). – Paul Bellora Apr 24 '13 at 23:21
No never omit it, that's why it gives a warning. – durron597 Apr 25 '13 at 04:16

1 Answers1