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

[Maurizio Cimadamore]

On Thu, 2 Oct 2025 10:51:08 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.

src/java.base/share/classes/java/util/LazyCollections.java line 255:

> 253:     }
> 254: 
> 255:     interface LenientList<E> extends List<E> {

Ok, this seems needed to give access to `getAcquire` from sublists created from other sublists...

src/java.base/share/classes/java/util/LazyCollections.java line 360:

> 358: 
> 359:         @Stable
> 360:         private final Set<K> keySet;

I believe putting the field in here might cause some redundancies -- for instance LazyMap extends this class and addss a `Map<K, Integer>`, from which you can clearly derive the key set...

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/27605#discussion_r2426326166
PR Review Comment: https://git.openjdk.org/jdk/pull/27605#discussion_r2426329562