<i18n dev> RFR: 8366178: Implement JEP 526: Lazy Constants (Second Preview) [v12]

[Maurizio Cimadamore]

On Fri, 17 Oct 2025 09:25:01 GMT, Per Minborg <pminborg at openjdk.org> wrote:

>> Implement JEP 526: Lazy Constants (Second Preview)
>> 
>> The lazy list/map implementations are broken out from `ImmutableCollections` to a separate class.
>> 
>> The old benchmarks are not moved/renamed to allow comparison with previous releases.
>> 
>> `java.util.Optional` is updated so that its field is annotated with `@Stable`.  This is to allow `Optional` instances to be held in lazy constants and still provide constant folding.
>
> Per Minborg has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Update javadocs

src/java.base/share/classes/java/lang/LazyConstant.java line 46:

> 44:  * A lazy constant is created using the factory method
> 45:  * {@linkplain LazyConstant#of(Supplier) LazyConstant.of({@code <computing function>})}.
> 46:  * When created, the contents (and hence the lazy constant itself) is <em>not initialized</em>.

"When created, the lazy constant is not initialized, meaning it has no contents."

E.g. it's the lazy constant that is initialized/not initialized. The content "just is". (or "is not", if not initialized).

src/java.base/share/classes/java/lang/LazyConstant.java line 47:

> 45:  * {@linkplain LazyConstant#of(Supplier) LazyConstant.of({@code <computing function>})}.
> 46:  * When created, the contents (and hence the lazy constant itself) is <em>not initialized</em>.
> 47:  * The contents (of type {@code T}) can then be <em>initialized</em>

Again, "a lazy constant can be initialized, and its content retrieved, by calling get"

src/java.base/share/classes/java/lang/LazyConstant.java line 50:

> 48:  * (and retrieved) by calling {@linkplain #get()}. The first time {@linkplain #get()}
> 49:  * is called, the underlying <em>computing function</em> (provided at construction) will
> 50:  * be invoked and the result will be used to initialize the contents. Once initialized,

"and the result will be used to initialize the lazy constant. Once a lazy constant is initialized, its contents can never change..."

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PR Review Comment: https://git.openjdk.org/jdk/pull/27605#discussion_r2439058429
PR Review Comment: https://git.openjdk.org/jdk/pull/27605#discussion_r2439060624
PR Review Comment: https://git.openjdk.org/jdk/pull/27605#discussion_r2439064085