Re: Warnings and collections
"Patricia Shanahan" <pats@acm.org> wrote in message
news:3Zd3g.3230$DT5.2140@newsread3.news.pas.earthlink.net...
Mike Schilling wrote:
"Patricia Shanahan" <pats@acm.org> wrote in message
news:MJE2g.6393$BS2.6240@newsread1.news.pas.earthlink.net...
I'm picking up a project I last worked on about a year, and one JDK
version, ago. It makes extensive use of java.util collections.
I just did a rebuild, and got 100 "Type safety" warnings. It used
to be warning-free.
Can you show some of the statements that cause warnings? We'll be in the
same state before long (code we don't want to touch that we'll be
compiling under 1.5) and I'd like to know what to watch out for.
Sure. Here's a typical case:
Type safety: The method get(int) belongs to the raw type List.
References to generic type List<E> should be parameterized
The source code line is:
Shop s = (Shop) allShops.get(j);
where allShops is declared as:
private static List allShops = new ArrayList();
Here's another form:
Type safety: The expression of type FileTimes.TimeComparator needs
unchecked conversion to conform to Comparator<? super T>
The source code line is:
Collections.sort(files, new TimeComparator());
Unfortunately, I don't see anything that can be done to make a program
using java.util collections work in 1.4 and also be warning-clean in 1.5.
What I don't understand ...
OK, *among* the things I don't understand is why the raw type can't be
defined as the moral equivalent of TYPE<Object> (in a type which so declares
it, not for all types). That would be correct for the java.util.collections
generics, at least, and would remove this sort of silly warning. You' still
get a warning when you passed, say, List<String> to a method that expects a
raw List, but that's a sensible warning, and comes from mixing 1.4 and 1.5
code.