8273261: Replace 'while' cycles with iterator with enhanced-for in java.base #5328

turbanoff · 2021-09-01T07:37:53Z

There are few places in code where manual while loop is used with Iterator to iterate over Collection.
Instead of manual while cycles it's preferred to use enhanced-for cycle instead: it's less verbose, makes code easier to read and it's less error-prone.
It doesn't have any performance impact: java compiler generates similar code when compiling enhanced-for cycle.

Similar cleanups:

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Issue

JDK-8273261: Replace 'while' cycles with iterator with enhanced-for in java.base

Reviewers

Daniel Fuchs (@dfuch - Reviewer)
Roger Riggs (@RogerRiggs - Reviewer)
Iris Clark (@irisclark - Reviewer)
Sean Mullan (@seanjmullan - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk pull/5328/head:pull/5328
$ git checkout pull/5328

Update a local copy of the PR:
$ git checkout pull/5328
$ git pull https://git.openjdk.java.net/jdk pull/5328/head

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Checkout this PR locally:
$ git pr checkout 5328

View PR using the GUI difftool:
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https://git.openjdk.java.net/jdk/pull/5328.diff

…base

bridgekeeper · 2021-09-01T07:39:06Z

👋 Welcome back turbanoff! 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 · 2021-09-01T07:40:45Z

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

core-libs
net
security

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.

turbanoff · 2021-09-02T06:55:31Z

Tested "tier2" on linux-x86_64-server-fastdebug Ubuntu 21.04

==============================
Test summary
==============================
   TEST                                              TOTAL  PASS  FAIL ERROR   
>> jtreg:test/jdk:tier2                               3772  3771     1     0 <<
   jtreg:test/langtools:tier2                           11    11     0     0   
   jtreg:test/jaxp:tier2                               452   452     0     0   
==============================
TEST FAILURE

Only one test java/nio/file/FileStore/Basic.java failed, but it fails without my changes too.

----------System.out:(46/2591)----------
/sys (sysfs) (name=sysfs type=sysfs)
/proc (proc) (name=proc type=proc)
/dev (udev) (name=udev type=devtmpfs)
/dev/pts (devpts) (name=devpts type=devpts)
/run (tmpfs) (name=tmpfs type=tmpfs)
/ (/dev/sda3) (name=/dev/sda3 type=ext4)
/sys/kernel/security (securityfs) (name=securityfs type=securityfs)
/dev/shm (tmpfs) (name=tmpfs type=tmpfs)
/run/lock (tmpfs) (name=tmpfs type=tmpfs)
/sys/fs/cgroup (tmpfs) (name=tmpfs type=tmpfs)
/sys/fs/cgroup/unified (cgroup2) (name=cgroup2 type=cgroup2)
/sys/fs/cgroup/systemd (cgroup) (name=cgroup type=cgroup)
/sys/fs/pstore (pstore) (name=pstore type=pstore)
/sys/fs/bpf (none) (name=none type=bpf)
/sys/fs/cgroup/perf_event (cgroup) (name=cgroup type=cgroup)
/sys/fs/cgroup/cpuset (cgroup) (name=cgroup type=cgroup)
/sys/fs/cgroup/hugetlb (cgroup) (name=cgroup type=cgroup)
/sys/fs/cgroup/rdma (cgroup) (name=cgroup type=cgroup)
/sys/fs/cgroup/net_cls,net_prio (cgroup) (name=cgroup type=cgroup)
/sys/fs/cgroup/blkio (cgroup) (name=cgroup type=cgroup)
/sys/fs/cgroup/freezer (cgroup) (name=cgroup type=cgroup)
/sys/fs/cgroup/cpu,cpuacct (cgroup) (name=cgroup type=cgroup)
/sys/fs/cgroup/devices (cgroup) (name=cgroup type=cgroup)
/sys/fs/cgroup/pids (cgroup) (name=cgroup type=cgroup)
/sys/fs/cgroup/memory (cgroup) (name=cgroup type=cgroup)
/proc/sys/fs/binfmt_misc (systemd-1) (name=systemd-1 type=autofs)
/sys/kernel/tracing (tracefs) (name=tracefs type=tracefs)
/dev/mqueue (mqueue) (name=mqueue type=mqueue)
/sys/kernel/debug (debugfs) (name=debugfs type=debugfs)
/dev/hugepages (hugetlbfs) (name=hugetlbfs type=hugetlbfs)
/sys/fs/fuse/connections (fusectl) (name=fusectl type=fusectl)
/sys/kernel/config (configfs) (name=configfs type=configfs)
/snap/core18/1997 (/dev/loop0) (name=/dev/loop0 type=squashfs)
/snap/gnome-3-34-1804/66 (/dev/loop2) (name=/dev/loop2 type=squashfs)
/snap/gnome-3-34-1804/72 (/dev/loop3) (name=/dev/loop3 type=squashfs)
/snap/core18/2128 (/dev/loop1) (name=/dev/loop1 type=squashfs)
/snap/gtk-common-themes/1514 (/dev/loop4) (name=/dev/loop4 type=squashfs)
/snap/snapd/12704 (/dev/loop8) (name=/dev/loop8 type=squashfs)
/snap/gtk-common-themes/1515 (/dev/loop5) (name=/dev/loop5 type=squashfs)
/snap/snap-store/547 (/dev/loop7) (name=/dev/loop7 type=squashfs)
/snap/snap-store/518 (/dev/loop6) (name=/dev/loop6 type=squashfs)
/snap/snapd/12883 (/dev/loop9) (name=/dev/loop9 type=squashfs)
/boot/efi (/dev/sda2) (name=/dev/sda2 type=vfat)
/run/user/1000 (tmpfs) (name=tmpfs type=tmpfs)
/run/user/1000/gvfs (gvfsd-fuse) (name=gvfsd-fuse type=fuse.gvfsd-fuse)
/run/user/1000/doc (portal) (name=portal type=fuse.portal)
----------System.err:(18/1172)----------
java.nio.file.FileSystemException: /run/user/1000/doc: Operation not permitted
	at java.base/sun.nio.fs.UnixException.translateToIOException(UnixException.java:100)
	at java.base/sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:106)
	at java.base/sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:111)
	at java.base/sun.nio.fs.UnixFileStore.readAttributes(UnixFileStore.java:115)
	at java.base/sun.nio.fs.UnixFileStore.getTotalSpace(UnixFileStore.java:122)
	at Basic.doTests(Basic.java:135)
	at Basic.main(Basic.java:49)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run(MainActionHelper.java:312)
	at java.base/java.lang.Thread.run(Thread.java:833)

openjdk · 2021-09-02T06:56:23Z

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openjdk · 2021-09-02T06:56:42Z

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openjdk · 2021-09-02T06:56:54Z

@turbanoff Unknown command dev - for a list of valid commands use /help.

openjdk · 2021-09-02T06:57:08Z

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mlbridge · 2021-09-02T07:07:43Z

Webrevs

00: Full (79c44a06)

dfuch

Generally this looks like a good improvement as the resulting code becomes more readable.
Changes in sun/net or jar index classes look fine. Please obtain approval from maintainers of the other areas before integrating.

openjdk · 2021-09-02T09:40:43Z

@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:

8273261: Replace 'while' cycles with iterator with enhanced-for in java.base

Reviewed-by: dfuchs, rriggs, iris, mullan

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 31 new commits pushed to the master branch:

8c37909: 8273234: extended 'for' with expression of type tvar causes the compiler to crash
28ba78e: 8244675: assert(IncrementalInline || (_late_inlines.length() == 0 && !has_mh_late_inlines()))
d05494f: 8266239: Some duplicated javac command-line options have repeated effect
93eec9a: 8272776: NullPointerException not reported
7b023a3: 8273257: jshell doesn't compile a sealed hierarchy with a sealed interface and a non-sealed leaf
f17ee0c: 8273263: Incorrect recovery attribution of record component type when j.l.Record is unavailable
fa9c865: 8273112: -Xloggc: should override -verbose:gc
dd87181: 8214761: Bug in parallel Kahan summation implementation
7fff22a: 8272805: Avoid looking up standard charsets
92b05fe: 8273251: Call check_possible_safepoint() from SafepointMechanism::process_if_requested()
... and 21 more: https://git.openjdk.java.net/jdk/compare/e600fe1a1a57d7e4060b3a1b9a8ecdb65664a506...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 (@dfuch, @RogerRiggs, @irisclark, @seanjmullan) 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).

RogerRiggs

LGTM

For the security related code a second reviewer would be good.

turbanoff · 2021-09-02T16:49:17Z

/integrate

openjdk · 2021-09-02T16:53:42Z

@turbanoff
Your change (at version 79c44a0) is now ready to be sponsored by a Committer.

seanjmullan

The security related changes look fine to me.

turbanoff · 2021-09-23T20:01:19Z

Can someone sponsor changes, please? I believe we have enough approvals.

RogerRiggs · 2021-09-23T20:03:09Z

/sponsor

openjdk · 2021-09-23T20:04:42Z

Going to push as commit 56b8b35.
Since your change was applied there have been 287 commits pushed to the master branch:

0aa63fe: 8274216: ProblemList 2 serviceability/dcmd/gc tests with ZGC on linux-all and windows-all
5ffbe75: 8274195: Doc cleanup in java.nio.file
1fdc656: 8274175: (fc) java/nio/channels/FileChannel/Transfer2GPlus.java still failed in timeout
3b1b8fc: 8269850: Most JDK releases report macOS version 12 as 10.16 instead of 12.0
1b7f4b7: 8274169: HotSpot Style Guide has stale link to chromium style guide
653a612: 8270156: Add "randomness" and "stress" keys to JTreg tests which use StressGCM, StressLCM and/or StressIGVN
66ce09f: 8272703: StressSeed should be set via FLAG_SET_ERGO
c434528: 8273546: DecimalFormat documentation contains literal HTML character references
d098751: 8273916: Remove 'special' ranking
4f3b626: 8271567: AArch64: AES Galois CounterMode (GCM) interleaved implementation using vector instructions
... and 277 more: https://git.openjdk.java.net/jdk/compare/e600fe1a1a57d7e4060b3a1b9a8ecdb65664a506...master

Your commit was automatically rebased without conflicts.

openjdk · 2021-09-23T20:04:58Z

@RogerRiggs @turbanoff Pushed as commit 56b8b35.

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

[PATCH] Replace while cycles with iterator with enhanced-for in java.…

79c44a0

…base

openjdk bot added security core-libs net labels Sep 1, 2021

turbanoff changed the title ~~[PATCH] Replace while cycles with iterator with enhanced-for in java.base~~ 8273261: Replace 'while' cycles with iterator with enhanced-for in java.base Sep 2, 2021

openjdk bot added the rfr label Sep 2, 2021

dfuch approved these changes Sep 2, 2021

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openjdk bot added the ready label Sep 2, 2021

RogerRiggs approved these changes Sep 2, 2021

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openjdk bot added the sponsor label Sep 2, 2021

seanjmullan approved these changes Sep 3, 2021

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openjdk bot closed this Sep 23, 2021

openjdk bot added integrated and removed ready rfr labels Sep 23, 2021

openjdk bot removed the sponsor label Sep 23, 2021

turbanoff deleted the replace_while_with_enhanced-for_in_java.base branch Sep 23, 2021

8273261: Replace 'while' cycles with iterator with enhanced-for in java.base #5328

8273261: Replace 'while' cycles with iterator with enhanced-for in java.base #5328

turbanoff commented Sep 1, 2021 •

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openjdk bot commented Sep 23, 2021

8273261: Replace 'while' cycles with iterator with enhanced-for in java.base #5328

8273261: Replace 'while' cycles with iterator with enhanced-for in java.base #5328

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turbanoff commented Sep 1, 2021 • edited by openjdk[bot] bot

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