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

[Jorn Vernee]

On Wed, 12 Nov 2025 15:23:25 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/lang/LazyConstant.java line 169:
> 
>> 167:  *          a lazy constant {@linkplain java.lang.ref##reachability strongly references}
>> 168:  *          it contents. Hence, a lazy constant will hold its contents until
>> 169:  *          the lazy constant itself is collected (if ever).
> 
> Maybe you could avoid the word 'collected' here, as there are no other references to the GC in this section, and no link to what GC is/does. i.e. I think 'collected' is not well-defined enough to be used here.
> 
> Suggestion:
> 
>  *          it contents. Hence, the contents of a lazy constant will be reachable as long
>  *          as the lazy constant itself is reachable.

Alternatively you could say something like 'becomes eligible for garbage collection', but I think defining the spec in terms of reachability is better, since that has a better definition in `java.lang.ref##reachability`.

> src/java.base/share/classes/java/util/Map.java line 1765:
> 
>> 1763:      * at most once per key, even in a multi-threaded environment. Competing
>> 1764:      * threads accessing a value already under computation will block until an element
>> 1765:      * is computed or an exception is thrown by the computing thread.
> 
> I think technically it's more correct to say something like '... or the computing function completes abnormally'. Since, if an exception is throw inside the computing function (by the computing thread), it may be caught and handled inside the computing function as well.

(Same for List)

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PR Review Comment: https://git.openjdk.org/jdk/pull/27605#discussion_r2518789003
PR Review Comment: https://git.openjdk.org/jdk/pull/27605#discussion_r2518834700