RFR: 8355369: Remove setAccessible usage for setting final fields in java.util.concurrent [v2]

[Doug Lea]

On Wed, 23 Apr 2025 17:54:03 GMT, Chen Liang <liach at openjdk.org> wrote:

>> I wonder if we could just change it to return `new ConcurrentSkipListSet<>(m)`. COWAL could be changed to return a new object too.
>
> The set only has a map field, and AbstractSet does not define any additional field. The map should be fine too - two fields in AbstractMap are cleared when cloning happens, so recreating a map from a constructor should have the same effect. (Note a significant field `head` is not cleared upon clone, but seems immediately replaced later in `buildFromSorted`). Both should still be fine with this new return values.

As others have mentioned, clone() needs to be re-checked wrt issuing final field fences. But can be conservatively done so here anyway.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24821#discussion_r2058163496