RFR: 8378759: Make ZipFile.CleanableResource.inflaterCache field final [v2]

[Chen Liang]

On Thu, 26 Feb 2026 13:39:51 GMT, Eirik Bjørsnøs <eirbjo at openjdk.org> wrote:

>> Please review this cleanup PR where we simplify synchronization on ZipFile's inflater cache.
>> 
>> Currently, the `ZipFile.CleanableResource.inflaterCache` field is non-final, is used in synchronization and is set to `null` to indicate a closed inflater cache. This complicates the state considerations for synchronization, requiring double-checking that the cache does not close under us. Generally, correctness of synchronizing on a non-final field which can also be null is hard to reason about.
>> 
>> This PR marks the `inflaterCache` field as `final` and introduces a boolean flag field to model the closed state explicitly. This allows synchronization to be simplified, double-checking to be removed and the closed state to be more obvious. If we want the future ZipFile to be less mutable, this is one step in that direction.
>> 
>> Cleanup refactoring, `noreg-cleanup`
>
> Eirik Bjørsnøs has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Reduce memory retained by a closed ZipFile

I don't think this patch brings much value; the old model was working fine, and people already identified a few regressions with this supposedly optimization. It's not worth reviewers' time to go through "hey there's a specific undocumented caller constraint to this method that I hope will continue to work by chance" for a supposedly stylistic improvement.

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PR Comment: https://git.openjdk.org/jdk/pull/29937#issuecomment-3967639980