RFR: 8366178: Implement JEP 526: Lazy Constants (Second Preview) [v25]

[Per Minborg]

On Wed, 12 Nov 2025 16:32:28 GMT, Jorn Vernee <jvernee at openjdk.org> wrote:

>> Per Minborg has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 112 commits:
>> 
>>  - Clarify toString spec
>>  - Merge branch 'master' into lazy-constants
>>  - Add @AOTSafeClassInitializer
>>  - Address comments in PR
>>  - Fix merge mistake
>>  - Merge master
>>  - Rework toString implementations
>>  - Update after doc comments
>>  - Merge branch 'master' into lazy-constants
>>  - Revert the AbstractMap.keySet @Stable annotation
>>  - ... and 102 more: https://git.openjdk.org/jdk/compare/76a1109d...1f439bec
>
> src/java.base/share/classes/java/util/LazyCollections.java line 607:
> 
>> 605:         assert Thread.holdsLock(mutex) : index + "didn't hold " + mutex;
>> 606:         // We know we hold the monitor here so plain semantic is enough
>> 607:         if (array[index] == null) {
> 
> This should always be true when we get here, right?

This is just an extra safety net to emulate a CAS op (while we are holding the monitor).

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PR Review Comment: https://git.openjdk.org/jdk/pull/27605#discussion_r2527936851