RFR: 8350880: (zipfs) Add support for read-only zip file systems [v12]

[Lance Andersen]

On Wed, 21 May 2025 23:30:18 GMT, David Beaumont <duke at openjdk.org> wrote:

>> Adding read-only support to ZipFileSystem.
>> 
>> The new `accessMode` environment property allows for readOnly and readWrite values, and ensures that the requested mode is consistent with what's returned.
>> 
>> This involved a little refactoring to ensure that "read only" state was set initially and only unset at the end of initialization if appropriate.
>> 
>> By making 2 methods return values (rather than silently set non-final fields as a side effect) it's now clear in what order fields are initialized and which are final (sadly there are still non-final fields, but only a split of this class into two types can fix that, since determining multi-jar support requires reading the file system).
>
> David Beaumont has updated the pull request incrementally with one additional commit since the last revision:
> 
>   More tweaking...

src/jdk.zipfs/share/classes/jdk/nio/zipfs/ZipFileSystem.java line 1451:

> 1449:         }
> 1450:         int version;
> 1451:         if (o instanceof String) {

Any reason to not use:

> 
    if (o instanceof String s) {
        if (s.equals("runtime")) {
            version = Runtime.version().feature();
        } else else if (s.matches("^[1-9][0-9]*$")) { {
            version = Version.parse(s).feature();;
            }
    }

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PR Review Comment: https://git.openjdk.org/jdk/pull/25178#discussion_r2104803699