On Wed, 10 Jun 2026 07:20:00 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 2798 commits: > > - Merge remote-tracking branch 'valhalla/lworld' into > jep401_sub_review_8317279 > - 8386239: [lworld] Update jdk/java/util/Arrays/ArraysEqCmpTest.java > > Reviewed-by: liach > - 8386242: [lworld] Simplify and clarify StrictProcessor > > Reviewed-by: dsimms > - 8386140: [lworld] FieldReflector using wrong Class argument > > Reviewed-by: alanb, dsimms > - 8386216: [lworld] Rollback meaningless diff in EventClassBuilder > > Reviewed-by: dsimms > - 8385170: [lworld] Serialization spec needs to allow abstract value classes > like Number > > Reviewed-by: liach > - 8385980: [lworld] Standardize pattern for preview value class generation > > Reviewed-by: liach > - 8386086: [lworld] > sun/jvmstat/monitor/MonitoredVm/MonitorVmStartTerminate.java should be > removed from problem list > > Reviewed-by: liach, dcubed > - Merge > > Merge jdk-28+1 > - 8386090: [lworld] Redundant test changes in lworld versus mainline > > Reviewed-by: vromero > - ... and 2788 more: https://git.openjdk.org/jdk/compare/92298786...4d6d2888 I’ve reviewed java.lang.classfile and com.sun.tools.javap, and apart from the comments below it looks good. src/java.base/share/classes/jdk/internal/classfile/impl/AccessFlagsImpl.java line 62: > 60: ? null // Try to guess for older preview features > 61: : VM.isSupportedClassFileVersion(major, minor) ? > ClassFileFormatVersion.fromMajor(major) > 62: : > ClassFileFormatVersion.latest(); // Fallback `ClassFileFormatVersion` parsed from a class file appears to be somewhat inconsistent. It is set to `null` for all preview class versions, although I assume the intent is for `PreviewAccessFlags` to be used only with the latest major class version. Conversely, it is set to `latest()` for clearly unsupported class versions. However, the Class-File API should not attempt to parse unsupported class versions in the first place and should fail instead. src/java.base/share/classes/jdk/internal/classfile/impl/ClassRemapperImpl.java line 88: > 86: map(ps.asSymbol())).toList())); > 87: case LoadableDescriptorsAttribute pa -> > 88: > clb.with(LoadableDescriptorsAttribute.of(pa.loadableDescriptors())); `LoadableDescriptorsAttribute` is not remapped, just copy-pasted. test/jdk/jdk/classfile/VerifierSelfTest.java line 219: > 217: .ifThen(CodeBuilder::nop) > 218: .return_() > 219: .with(new > CloneAttribute(StackMapTableAttribute.of(List.of()))) How preview run affects testing SMTA? ------------- PR Review: https://git.openjdk.org/jdk/pull/31123#pullrequestreview-4498726418 PR Review Comment: https://git.openjdk.org/jdk/pull/31123#discussion_r3414587043 PR Review Comment: https://git.openjdk.org/jdk/pull/31123#discussion_r3414702868 PR Review Comment: https://git.openjdk.org/jdk/pull/31123#discussion_r3414881559
