8297682: Use Collections.emptyIterator where applicable

[turbanoff]

Instead of Collections.emptyList().iterator() we can use Collections.emptyIterator() method.
Actual implementation of java.util.Collections.EmptyList#iterator does exactly this - just calls emptyIterator method.

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Progress

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Issue

• JDK-8297682: Use Collections.emptyIterator where applicable

Reviewers

• Sergey Tsypanov (@stsypanov - Author)
• Alan Bateman (@AlanBateman - Reviewer)
• Jaikiran Pai (@jaikiran - Reviewer)

Reviewing

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[openjdk]

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[stsypanov]

LGTM

[mlbridge]

Webrevs

• 00: Full (07f162df)

[AlanBateman]

The change to UnixFileSystem::getRootDirectories looks okay.

[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:

8297682: Use Collections.emptyIterator where applicable

Reviewed-by: stsypanov, alanb, jpai

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 424 new commits pushed to the master branch:

• 619b68c: 8294540: Remove Opaque2Node: it is broken and triggers assert
• 82561de: 8296384: [TESTBUG] sun/security/provider/SecureRandom/AbstractDrbg/SpecTest.java intermittently timeout
• 61b7093: 8297872: Non-local G1MonotonicArenaFreePool::_freelist_pool has non-trivial ctor/dtor
• 3b3bbe5: 8296907: VMError: add optional callstacks, siginfo for secondary errors
• a573923: 8297264: C2: Cast node is not processed again in CCP and keeps a wrong too narrow type which is later replaced by top
• b49fd92: 8298055: AArch64: fastdebug build fails after JDK-8247645
• 914ef07: 8297609: Add application/wasm MIME type for wasm file extension
• a71d91b: 8298067: Persistent test failures after 8296012
• 87572d4: 8298068: ProblemList tests failing due to JDK-8297235
• 0edb5d0: 8297683: Use enhanced-for cycle instead of Enumeration in java.security.jgss
• ... and 414 more: https://git.openjdk.org/jdk/compare/3baad069a65a0ac138a6aaabf451758672d12fbc...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.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[pavelrappo]

Alternatively, you could use the exception parameter to capture that comment:

} catch (SecurityException disallowed) {

[jaikiran]

UnixFileSystem change looks OK to me.

[turbanoff]

/integrate

[openjdk]

Going to push as commit 85f9b37.
Since your change was applied there have been 694 commits pushed to the master branch:

• f36e144: 8299025: BMPImageReader.java readColorPalette could use staggeredReadByteStream
• f56285c: 8299146: No copyright statement on ArtifactResolverException.java
• 396a9bf: 8298913: Add override qualifiers to Relocation classes
• 386db07: Merge
• f4d7f43: 8299123: [BACKOUT] 4512626 Non-editable JTextArea provides no visual indication of keyboard focus
• 03afec1: 8298162: Test PrintClasses hits assert when run with code that retransform classes
• 03d9927: 8298061: vmTestbase/nsk/sysdict/vm/stress/btree/btree012/btree012.java failed with "fatal error: refcount has gone to zero"
• 65fc058: 8298968: G1: Incorrect merged remset stats
• 8dfb6d7: 8298651: Serial: Remove MarkSweep::follow_klass
• de8153c: 8298526: JFR: Generate missing filename for time-bound recordings
• ... and 684 more: https://git.openjdk.org/jdk/compare/3baad069a65a0ac138a6aaabf451758672d12fbc...master

Your commit was automatically rebased without conflicts.

[openjdk]

@turbanoff Pushed as commit 85f9b37.

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