On Fri, 26 Jun 2026 06:40:49 GMT, David Simms <[email protected]> wrote:
>> This is a "*sub-review pull request*" for the first >> [preview](https://openjdk.org/jeps/12) of [JEP 401: Value Classes and >> Objects](https://openjdk.org/jeps/401), specifically >> [JDK-8317279](https://bugs.openjdk.org/browse/JDK-8317279): Standard library >> implementation of value classes and objects >> >>> [!NOTE] >>> This pull request and the other sub-review pull requests listed below are >>> based on the "*master pull request*" >>> (https://github.com/openjdk/jdk/pull/31120). It contains the same full set >>> of code changes as the "*master pull request*" to preserve the full >>> implementation context; the language compiler, JVM, and standard library >>> changes are intertwined. This separate pull requests exist only to >>> subdivide the review and related discussion by area. >> >> Other areas for review: >> >> - [JDK-8317277](https://bugs.openjdk.org/browse/JDK-8317277): Java language >> implementation of value classes and objects >> - https://github.com/openjdk/jdk/pull/31121 >> - [JDK-8317278](https://bugs.openjdk.org/browse/JDK-8317278): JVM >> implementation of value classes and objects >> - https://github.com/openjdk/jdk/pull/31122 >> >> Code changes resulting from the review process should be made in >> [`valhalla/lworld`](https://github.com/openjdk/valhalla/). >> >> `valhalla/lworld` is currently updated from `jdk/master` whenever a weekly >> [`jdk` tag](https://github.com/openjdk/jdk/tags) is created. At that time, >> code changes from `valhalla/lworld` will be propagated to the master pull >> request and to all sub-review pull requests, including this one. >> >> Ultimately, review sign-off will be recorded on the "*master pull request*", >> and this pull request will be closed without integration. >> >> This pull request has a large code surface area and often conflicts with >> `jdk/master` on a daily basis. Refer to >> [`valhalla/lworld`](https://github.com/openjdk/valhalla/) for the latest >> state of the project code, keeping in mind that it may lag several days >> behind `jdk/master`. Both repositories may be needed as references during >> review. >> >> # PR implementation description >> >> Here's a high-level overview of what's included here. >> >> ### Core object behaviors >> >> Introduced `Objects` methods to test for identity and `IdentityException` for >> test failures; revised definitions of `==` and `identityHashCode` to work on >> the >> fields of value objects. >> >> - `src/java.base/share/classes/java/lang` >> - `src/java.base/share/classes/java/util` >> - `src/java.base/share/classes/java/lang/runtime` >> - ... > > David Simms has updated the pull request with a new target base due to a > merge or a rebase. The pull request now contains 2859 commits: > > - Merge branch '8317277' into jep401_sub_review_8317279 > - Merge remote-tracking branch 'valhalla/lworld' into 8317277 > - Merge > > Merge jdk-28+4 > - 8386963: [lworld] Improve the exception message from Object > synchronization methods on value objects > > Reviewed-by: dholmes, alanb > - 8387300: [lworld] Minor review comments in javac > > Reviewed-by: vromero > - 8387192: [lworld] Review comment drop for core libs > > Reviewed-by: jvernee, vromero > - 8386999: [lworld] C2: assert(is_dead_loop_safe()) failed: shouldn't be > cleared yet > > Reviewed-by: qamai, vlivanov > - 8386787: [lworld] > compiler/valhalla/inlinetypes/TestValueConstruction.java#StressIncrementalInliningDontInlineMyAbstractInit > timed out > > Reviewed-by: phubner, chagedorn > - 8386995: [lworld] Duplicate value classes are a preview feature warning > > Reviewed-by: alanb, vromero > - 8383389: [lworld] Augment AOTMapLogger::print_oop_details to support flat > arrays with oops > > Reviewed-by: iklam, fparain > - ... and 2849 more: https://git.openjdk.org/jdk/compare/193de1b1...cdbe55a9 src/java.base/share/classes/java/lang/doc-files/ValueBased.html line 50: > 48: visible change in the behavior of the class's methods;</li> > 49: <li>the class performs no synchronization using an instance's > monitor;</li> > 50: <li>the class does not declare (or discourages use of) accessible > constructors;</li> > the class does not declare (or discourages use of) accessible constructors; Does this apply for value classes that are being proposed in this JEP? As far as I remember, I haven't seen any text which states or discourages the use of constructors for value object construction. In fact, on the contrary, in one of the review comments in this PR for a different discussion, it has been rightly pointed out that in recent times there have been efforts to undeprecate previously deprecated-for-removal constructors of the primitive wrapper classes. For example https://bugs.openjdk.org/browse/JDK-8354335. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/31123#discussion_r3498274008
