8336278: Micro-optimize Replace String.format("%n") to System.lineSeparator

[wenshao]

There are three places in the JDK code where String.format("%n") is used. This is actually equivalent to System.lineSeparator and does not require the implementation of String.format.

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8336278: Micro-optimize Replace String.format("%n") to System.lineSeparator (Enhancement - P4)

Reviewers

• Doug Simon (@dougxc - Reviewer)
• Aleksey Shipilev (@shipilev - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/20149/head:pull/20149
$ git checkout pull/20149

Update a local copy of the PR:
$ git checkout pull/20149
$ git pull https://git.openjdk.org/jdk.git pull/20149/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 20149

View PR using the GUI difftool:
$ git pr show -t 20149

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/20149.diff

Webrev

Link to Webrev Comment

[bridgekeeper]

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

[openjdk]

@wenshao 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:

8336278: Micro-optimize Replace String.format("%n") to System.lineSeparator

Reviewed-by: dnsimon, shade

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 12 new commits pushed to the master branch:

• 1f6e106: 8335684: Test ThreadCpuTime.java should pause like ThreadCpuTimeArray.java
• 84c74ad: 8335802: Improve startup speed HexFormat uses boolean instead of enum
• 4f312d6: 8336152: Remove unused forward declaration in classLoadInfo.hpp
• 34d8562: 8335902: Parallel: Refactor VM_ParallelGCFailedAllocation and VM_ParallelGCSystemGC
• 2fc7eb4: 8155030: The Menu Mnemonics are always displayed for GTK LAF
• 559826c: 8332474: Tighten up ToolBox' JavacTask to not silently accept javac crash as a failure
• eec0e15: 8335619: Add an @APinote to j.l.i.ClassFileTransformer to warn about recursive class loading and ClassCircularityErrors
• 9b6f6c5: 8336082: Fix -Wzero-as-null-pointer-constant warnings in SimpleCompactHashtable
• 7a62032: 8336081: Fix -Wzero-as-null-pointer-constant warnings in JVMTypedFlagLimit ctors
• f677b90: 8267887: RMIConnector_NPETest.java fails after removal of RMI Activation (JDK-8267123)
• ... and 2 more: https://git.openjdk.org/jdk/compare/81a0d1ba03bbdbe718302b3925cdc207d5d05232...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 (@dougxc, @shipilev) 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).

[openjdk]

@wenshao The following labels will be automatically applied to this pull request:

• graal
• hotspot

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing lists. If you would like to change these labels, use the /label pull request command.

[mlbridge]

Webrevs

• 00: Full (829da3e1)

[dougxc]

Looks good and trivial to me.

[shipilev]

Hah! Yes, it makes no sense to call into String.format to just get the line separator.

[wenshao]

/integrate

[openjdk]

@wenshao
Your change (at version 829da3e) is now ready to be sponsored by a Committer.

[liach]

/sponsor

[openjdk]

Going to push as commit 4957145.
Since your change was applied there have been 12 commits pushed to the master branch:

• 1f6e106: 8335684: Test ThreadCpuTime.java should pause like ThreadCpuTimeArray.java
• 84c74ad: 8335802: Improve startup speed HexFormat uses boolean instead of enum
• 4f312d6: 8336152: Remove unused forward declaration in classLoadInfo.hpp
• 34d8562: 8335902: Parallel: Refactor VM_ParallelGCFailedAllocation and VM_ParallelGCSystemGC
• 2fc7eb4: 8155030: The Menu Mnemonics are always displayed for GTK LAF
• 559826c: 8332474: Tighten up ToolBox' JavacTask to not silently accept javac crash as a failure
• eec0e15: 8335619: Add an @APinote to j.l.i.ClassFileTransformer to warn about recursive class loading and ClassCircularityErrors
• 9b6f6c5: 8336082: Fix -Wzero-as-null-pointer-constant warnings in SimpleCompactHashtable
• 7a62032: 8336081: Fix -Wzero-as-null-pointer-constant warnings in JVMTypedFlagLimit ctors
• f677b90: 8267887: RMIConnector_NPETest.java fails after removal of RMI Activation (JDK-8267123)
• ... and 2 more: https://git.openjdk.org/jdk/compare/81a0d1ba03bbdbe718302b3925cdc207d5d05232...master

Your commit was automatically rebased without conflicts.

[openjdk]

@liach @wenshao Pushed as commit 4957145.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.