8274879: Replace uses of StringBuffer with StringBuilder within java.base classes

[turbanoff]

StringBuffer is a legacy synchronized class. There are more modern alternatives which perform better:

1. Plain String concatenation should be preferred
2. StringBuilder is a direct replacement to StringBuffer which generally have better performance

In JDK-8264029 I migrated only usages which were automatically detected by IDEA. It turns out there are more usages which can be migrated.

---

Progress

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Issue

• JDK-8274879: Replace uses of StringBuffer with StringBuilder within java.base classes

Reviewers

• Naoto Sato (@naotoj - Reviewer)

Reviewing

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$ git checkout pull/5432

Update a local copy of the PR:
$ git checkout pull/5432
$ git pull https://git.openjdk.java.net/jdk pull/5432/head

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$ git pr checkout 5432

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$ git pr show -t 5432

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https://git.openjdk.java.net/jdk/pull/5432.diff

[bridgekeeper]

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[openjdk]

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[mlbridge]

Webrevs

• 01: Full - Incremental (c8d68c2a)
• 00: Full (14005d1d)

[openjdk]

@turbanoff 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:

8274879: Replace uses of StringBuffer with StringBuilder within java.base classes

Reviewed-by: naoto

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 252 new commits pushed to the master branch:

• 9f75d5c: 8259948: Aarch64: Add cast nodes for Aarch64 Neon backend
• d98b7c2: 8202926: Test java/awt/Focus/WindowUpdateFocusabilityTest/WindowUpdateFocusabilityTest.html fails
• b0d1e4f: 8273585: String.charAt performance degrades due to JDK-8268698
• 7addcd7: 8276034: ProblemList gtest dll_address_to_function_and_library_name on macosx-x64
• 2448b3f: 8275874: [JVMCI] only support aligned reads in c2v_readFieldValue
• f1f5e26: 8275872: Sync J2DBench run and analyze Makefile targets with build.xml
• 19f76c2: 8275079: Remove unnecessary conversion to String in java.net.http
• e5cd269: 8274944: AppCDS dump causes SEGV in VM thread while adjusting lambda proxy class info
• 82f4aac: 8259609: C2: optimize long range checks in long counted loops
• 574f890: 8275720: CommonComponentAccessibility.createWithParent isWrapped causes mem leak
• ... and 242 more: https://git.openjdk.java.net/jdk/compare/9945f7a0744db2470bcfa856e8f831b6a6eb2de8...master

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.

As you do not have Committer status in this project an existing Committer must agree to sponsor your change. Possible candidates are the reviewers of this PR (@naotoj) but any other Committer may sponsor as well.

➡️ To flag this PR as ready for integration with the above commit message, type /integrate in a new comment. (Afterwards, your sponsor types /sponsor in a new comment to perform the integration).

[turbanoff]

/integrate

[openjdk]

@turbanoff
Your change (at version c8d68c2) is now ready to be sponsored by a Committer.

[naotoj]

/sponsor

[openjdk]

Going to push as commit 9a3e954.
Since your change was applied there have been 263 commits pushed to the master branch:

• e6fa5fa: 8276063: ProblemList gtest dll_address_to_function_and_library_name on macosx-generic
• 809488b: 8276046: codestrings.validate_vm gtest fails on ppc64, s390
• 93be099: 4718400: Many quantities are held as signed that should be unsigned
• 168081e: 8270490: Charset.forName() taking fallback default value
• a292733: 8275975: Remove dead code in ciInstanceKlass
• 4060602: 8275800: Redefinition leaks MethodData::_extra_data_lock
• 485d658: 8275851: Deproblemlist open/test/jdk/javax/swing/JComponent/6683775/bug6683775.java
• b3f45f8: 8275689: [TESTBUG] Use color tolerance only for XRender in BlitRotateClippedArea test
• 6c05cc9: 8275863: Use encodeASCII for ASCII-compatible DoubleByte encodings
• 2f979ec: 8213120: java/awt/TextArea/AutoScrollOnSelectAndAppend/AutoScrollOnSelectAndAppend.java fails on mac10.13
• ... and 253 more: https://git.openjdk.java.net/jdk/compare/9945f7a0744db2470bcfa856e8f831b6a6eb2de8...master

Your commit was automatically rebased without conflicts.

[openjdk]

@naotoj @turbanoff Pushed as commit 9a3e954.

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