RFR: 8321139: jlink's man page does not document the --compress option correctly [v7]

[Jaikiran Pai]

On Tue, 25 Nov 2025 17:41:27 GMT, Ana Maria Mihalceanu <duke at openjdk.org> wrote:

>> This PR looks into aligning the behavior and documentation for `--compress` option and plugin of `jlink`:
>> 
>> - When an user provides `-c {0|1|2}` to `jlink`, then the tool should process it as when receiving `--compress={0|1|2}`. As these values are now deprecated, a warning should be issued to the end user.
>> - When an user provides `-c zip-[0-9]` to `jlink`, then the tool should process it as when receiving `--compress=zip-[0-9]`.
>> - When no compression level is given, meaning the `jlink` command does not contain either `-c` or `--compress` with a value, the default level selected is `zip-6`.
>> - The `--compress` option description reflects above behavior and warns that previous compression levels are deprecated to be removed in a future release.
>> - The `--plugin` option description reflects the implementation behavior and warns that previous compression levels are deprecated to be removed in a future release.
>> 
>> Some implementation details and choices:
>> - While current `jlink` man page states that the tool supports `-c={0|1|2}`, I inspired myself on how `javac` supports the shortened options https://docs.oracle.com/en/java/javase/25/docs/specs/man/javac.html#options.
>> - While `-c 0` and `--compress=0` produce the same compression level as of `zip-0`, I preferred not to tie the new compression level to the old value for the option. I believe that this approach would make it easier/cleaner to remove the code for the deprecated values (when their time comes).
>> - While `-c 2` and `--compress=2` produce the same compression level as of `zip-6`, I preferred not to tie the new compression level to the old value for the option. I believe that this approach would make it easier/cleaner to remove the code for the deprecated values (when their time comes).
>> - As I didn't affect the actual compression implementation, only the options, I tested only how the options are mapped. The actual set and validation of the options was not affected, hence I didn't change those tests.
>
> Ana Maria Mihalceanu has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Move test for invalid values from TaskHelperTest to JLinkTest.

src/jdk.jlink/share/classes/jdk/tools/jlink/resources/jlink.properties line 69:

> 67: main.opt.bind-services=\
> 68: \      --bind-services                   Link in service provider modules and\n\
> 69: \                                        their dependencies

I think we should leave this change (here and in one other place) out of this PR. There's https://bugs.openjdk.org/browse/JDK-8337422 which is tracking this and there's some discussion in that issue, which indicates that it's OK to do this change. But I think we should do it as part of JDK-8337422.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28359#discussion_r2563195225