RFR: 8352642: Reduce cost of JAR directory scan in ArchiveContainer

[Jason Zaugg]

On Sun, 23 Mar 2025 12:38:04 GMT, Jason Zaugg <jzaugg at openjdk.org> wrote:

> 8352642: Reduce cost of JAR directory scan in ArchiveContainer

src/jdk.compiler/share/classes/com/sun/tools/javac/file/JavacFileManager.java line 564:

> 562:         public ArchiveContainer(Path archivePath) throws IOException, ProviderNotFoundException {
> 563:             this.archivePath = archivePath;
> 564:             if (multiReleaseValue != null && archivePath.toString().endsWith(".jar")) {

The else branch, which uses `FileSystems.newFileSystem(archivePath, (ClassLoader)null); rather than  `jarFsProvider.newFileSystem`,  is unchanged in the PR. 

AFAICT that would only be taken when a client using `JavacFileManager` directly, omitting the `fm.handleOption(Option.MULTIRELEASE, .. )` call, or in a custom scenario with non-JAR archivess.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24176#discussion_r2009104482