RFR: 8287596: Reorg jdk.test.lib.util.ForceGC [v7]

[Xue-Lei Andrew Fan]

On Mon, 13 Jun 2022 22:37:52 GMT, Mandy Chung <mchung at openjdk.org> wrote:

>> Xue-Lei Andrew Fan has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains ten commits:
>> 
>>  - Merge
>>  - Merge master
>>  - Merge
>>  - add timeout parameter
>>  - rollback is not in this branch
>>  - rollback JDK-8287384
>>  - back to wait 1 second
>>  - Remove trailing white space
>>  - 8287596: Reorg jdk.test.lib.util.ForceGC
>
> test/jdk/java/lang/invoke/defineHiddenClass/UnloadingTest.java line 224:
> 
>> 222: 
>> 223:         boolean tryUnload() {
>> 224:             return ForceGC.wait(() -> weakRef.get() == null, 1000L);
> 
> This verifies that the reference will never become weakly unreachable, i.e. it remains strongly reachable.
> 
> I suggest to add a method default to 200ms (?) timeout scaled with the timeout factor and expect the specified condition will never met.   Maybe call it `ForceGC.neverTrue(BooleanSupplier)`?   Need to tune the base waiting time; for example if timeout factor is 4, then total wait would be 800 ms.

I see your points.

When I changed the waiting time to 1 second scaled with timeout factor, it looks like safe to use the ForceGC.wait() method for either cleanup and non-cleanup checking.  The default JTREG timeout for a test case is 120 seconds. 1 seconds may be small enough so that we could use it for both cases.

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PR: https://git.openjdk.org/jdk/pull/8979