8274525: Replace uses of StringBuffer with StringBuilder in java.xml

[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

Similar cleanups:

1. JDK-8264029 java.base
2. JDK-8264428 java.desktop
3. JDK-8264484 jdk.hotspot.agent

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• Change must be properly reviewed

Issue

• JDK-8274525: Replace uses of StringBuffer with StringBuilder in java.xml

Reviewers

• Joe Wang (@JoeWang-Java - Reviewer)
• Iris Clark (@irisclark - Reviewer)
• Naoto Sato (@naotoj - Reviewer)
• Daniel Fuchs (@dfuch - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk pull/5759/head:pull/5759
$ git checkout pull/5759

Update a local copy of the PR:
$ git checkout pull/5759
$ git pull https://git.openjdk.java.net/jdk pull/5759/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 5759

View PR using the GUI difftool:
$ git pr show -t 5759

Using diff file

Download this PR as a diff file:
https://git.openjdk.java.net/jdk/pull/5759.diff

[bridgekeeper]

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[openjdk]

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[mlbridge]

Webrevs

• 00: Full (69af74fc)

[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:

8274525: Replace uses of StringBuffer with StringBuilder in java.xml

Reviewed-by: joehw, iris, naoto, dfuchs

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 24 new commits pushed to the master branch:

• 292d7bb: 8274363: Transitively sealed classes not considered exhaustive in switches
• 1887028: 8269113: Javac throws when compiling switch (null)
• b7b78ff: 8274561: sun/net/ftp/TestFtpTimeValue.java timed out on slow machines
• 5e4b514: 8274550: c2i entry barriers read int as long on PPC
• 2e690ba: 8274322: Problems with oopDesc construction
• a8edd1b: 8274527: Minimal VM build fails after JDK-8273459
• 7326481: 8274393: Suppress more warnings on non-serializable non-transient instance fields in security libs
• 8215b2e: 8274398: Suppress more warnings on non-serializable non-transient instance fields in management libs
• 9573022: 8253197: vmTestbase/nsk/jvmti/StopThread/stopthrd007/TestDescription.java fails with "ERROR: DebuggeeSleepingThread: ThreadDeath lost"
• f08180f: 8274501: c2i entry barriers read int as long on AArch64
• ... and 14 more: https://git.openjdk.java.net/jdk/compare/97b28742b4d3083cadbe4dc10b625ec9fb944353...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 (@JoeWang-Java, @irisclark, @naotoj, @dfuch) 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 69af74f) is now ready to be sponsored by a Committer.

[dfuch]

/sponsor

[openjdk]

Going to push as commit 754bc82.
Since your change was applied there have been 82 commits pushed to the master branch:

• 4e7d7ca: 8273711: Remove redundant stream() call before forEach in jdk.jlink
• f3cedbe: 8274464: Remove redundant stream() call before forEach in java.* modules
• c10de35: 8262944: Improve exception message when automatic module lists provider class not in JAR file
• b8af6a9: 8273917: Remove 'leaf' ranking for Mutex
• c80a612: 8273381: Assert in PtrQueueBufferAllocatorTest.stress_free_list_allocator_vm
• 9759fcb: 8274496: Use String.contains() instead of String.indexOf() in java.desktop
• cdf8930: 8274625: Search field placeholder behavior
• df125f6: 8273410: IR verification framework fails with "Should find method name in validIrRulesMap"
• c74726d: 8274730: AArch64: AES/GCM acceleration is broken by the fix for JDK-8273297
• 2faced0: 8274738: ZGC: Use relaxed atomic load when reading bits in the live map
• ... and 72 more: https://git.openjdk.java.net/jdk/compare/97b28742b4d3083cadbe4dc10b625ec9fb944353...master

Your commit was automatically rebased without conflicts.

[openjdk]

@dfuch @turbanoff Pushed as commit 754bc82.

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