8373945: Use WB.fullGC() in ClassUnloader.unloadClass to force GC for vmTestbase tests

[sendaoYan]

Hi all,

This backport PR contains JDK-8373945 and JDK-8375485. These two PR try to use WB.fullGC() in ClassUnloader.unloadClass to force GC for vmTestbase tests, which will make test more robustness and run more quickly. Some of the tests touched by '8260555: Change the default TIMEOUT_FACTOR from 4 to 1' make this backport uncleanly, and only below 5 files backported uncleanly because of the diffrent copyright year. All other parts are cleanly.

Change has been verifed locally on linux-x64 by run all the releated tests. Test-fix only, no risk.

test/hotspot/jtreg/vmTestbase/gc/gctests/LargeObjects/large001/large001.java
test/hotspot/jtreg/vmTestbase/gc/gctests/LargeObjects/large002/TestDescription.java
test/hotspot/jtreg/vmTestbase/gc/gctests/LargeObjects/large003/TestDescription.java
test/hotspot/jtreg/vmTestbase/gc/gctests/LargeObjects/large004/TestDescription.java
test/hotspot/jtreg/vmTestbase/gc/gctests/LargeObjects/large005/TestDescription.java

Related tests list:

199.log

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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
• JDK-8373945 needs maintainer approval
• JDK-8375485 needs maintainer approval

Issues

• JDK-8373945: Use WB.fullGC() in ClassUnloader.unloadClass to force GC for vmTestbase tests (Enhancement - P4)
• JDK-8375485: Tests in vmTestbase/nsk are failing due to missing class unloading after 8373945 (Bug - P3)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk25u-dev.git pull/199/head:pull/199
$ git checkout pull/199

Update a local copy of the PR:
$ git checkout pull/199
$ git pull https://git.openjdk.org/jdk25u-dev.git pull/199/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 199

View PR using the GUI difftool:
$ git pr show -t 199

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk25u-dev/pull/199.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back syan! 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]

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

[openjdk]

This backport pull request has now been updated with issue from the original commit.

[mlbridge]

Webrevs

• 00: Full (c9875bcf)

[sendaoYan]

/issue JDK-8375485

[openjdk]

@sendaoYan
Adding additional issue to issue list: 8375485: Tests in vmTestbase/nsk are failing due to missing class unloading after 8373945.