RFR: 8375580: Avoid using ArrayDeque in jdk.internal.loader.URLClassPath [v2]

[Jaikiran Pai]

On Mon, 26 Jan 2026 13:32:20 GMT, Eirik Bjørsnøs <eirbjo at openjdk.org> wrote:

>> src/java.base/share/classes/jdk/internal/loader/URLClassPath.java line 139:
>> 
>>> 137:     public URLClassPath(URL[] urls,
>>> 138:                         URLStreamHandlerFactory factory) {
>>> 139:         // Reject null URLs
>> 
>> Nit - I think it would be better to clarify that it's intentional to (continue) to reject null element in the array. So may be reword this comment to "Reject null URL array or any null element in the array"?
>
> Yeah, the issue here is that `ArrayList` is null friendly while `ArrayDeque` was hostile.
> 
> So since there is no such thing as`Arrays::requireNonNullElements`, I used `List.of`, (as suggested by @stuart-marks in JDK-8301042).
> 
> But that seemed non-obvious and brittle, hence the addition of the comment.
> 
> What would you think about being explicit in the null check, such that the code documents itself:
> 
> 
>         // Reject null URL array or any null element in the array
>         Objects.requireNonNull(urls);
>         for (URL url : urls) {
>             Objects.requireNonNull(urls);
>         }
> 
>         this.searchPath = new ArrayList<>(Arrays.asList(urls));

I think using `List.of()` is the right thing to do, since its behaviour is specified. A iteration as proposed here would very likely be refactored later into a `List.of()` as a clean up, when someone spots this code.

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PR Review Comment: https://git.openjdk.org/jdk/pull/29288#discussion_r2727646276