8366214: [lworld] Use Objects.equals in HashMap and ConcurrentHashmap

[RogerRiggs]

As observed in JDK-8366043 [lworld] (LIFE = Legacy Idiom For Equality) causes performance regressions.
Updating HashMap and ConcurrentHashMap to use java.util.Objects.equals will make it easier to measure performance of options that remove or modify the use of ==

Replace constructs like:

-                        ((k = e.key) == key || (key != null && key.equals(k))))
with:
+                        Objects.equals(key, k))

The changes in ConcurrentHashMap are a bit different due to the use of null as a sentinel.

The order of arguments to the .equals methods must remain the same to ensure compatibility.

---

Progress

• Change must not contain extraneous whitespace

Issue

• JDK-8366214: [lworld] Use Objects.equals in HashMap and ConcurrentHashmap (Bug - P4)

Reviewers

• Chen Liang (@liach - Committer)

Reviewing

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[bridgekeeper]

👋 Welcome back rriggs! A progress list of the required criteria for merging this PR into lworld will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

@RogerRiggs This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8366214: [lworld] Use Objects.equals in HashMap and ConcurrentHashmap

Reviewed-by: liach

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At the time when this comment was updated there had been 221 new commits pushed to the lworld branch:

• 22e9d5f: Adjust testing 8366774
• 43c6b8a: Merge jdk
• c59e44a: 8357914: TestEmptyBootstrapMethodsAttr.java fails when run with TEST_THREAD_FACTORY=Virtual
• ... and 218 more: https://git.openjdk.org/valhalla/compare/bd1d97b7605144000a773a80e6dbc2ff923cb691...lworld

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

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[mlbridge]

Webrevs

• 00: Full (79fd2a1a)

[liach]

I think my concerns are addressed so far.

[RogerRiggs]

/integrate

[openjdk]

Going to push as commit c8d4a24.
Since your change was applied there have been 222 commits pushed to the lworld branch:

• 480094c: 8366802: [lworld] jdk/javadoc/doccheck/checks/jdkCheckLinks.java fails since jdk-26+26
• 22e9d5f: Adjust testing 8366774
• 43c6b8a: Merge jdk
• ... and 219 more: https://git.openjdk.org/valhalla/compare/bd1d97b7605144000a773a80e6dbc2ff923cb691...lworld

Your commit was automatically rebased without conflicts.

[openjdk]

@RogerRiggs Pushed as commit c8d4a24.

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