RFR: 8283276: java/io/ObjectStreamClass/ObjectStreamClassCaching.java fails with various GCs

[Aleksey Shipilev]

On Wed, 27 Jul 2022 12:30:43 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>>> ...I can take this over, unless you want to do it, Aleksey?
>> 
>> I find it dubious to try and guess what GCs would do with non-strong refs, but feel free. Don't reassign the bug yet, just see how messy that would be?
>
>> > ...I can take this over, unless you want to do it, Aleksey?
>> 
>> I find it dubious to try and guess what GCs would do with non-strong refs, but feel free. Don't reassign the bug yet, just see how messy that would be?
> 
> On the other hand, this test is in tier2, so it makes lots of testing with other GCs not clean. I would like to have this fix in, and *then* do any followups that might make the test more targeted.

> So how do we proceed @shipilev ? I open another issue or are you willing to accept my changes into your issue?

I prefer to commit the simpler (mine) version first, and the follow up with any more sophisticated attempt to fix it.

> It then basically tests just that newly constructed SoftReference is not cleared in the next moment after construction.

Yes, but not really. There is still a 100ms sleep and reference processing involved, which somewhat verifies that the cache is not blown away immediately/accidentally.

> Who is responsible to select the GC algorithm?

CIs routinely test existing suites with different GCs. The PR body contains a sample reproducer how that happens. If you are doing the separate `@run` statements, you need to also check for `@requires vm.gc.XXX`, etc.

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PR: https://git.openjdk.org/jdk/pull/9533