RFR(S): 8228960: [TESTBUG] containers/docker/TestJcmdWithSideCar.java: jcmd reports main class as 'Unknown'

David Holmes david.holmes at oracle.com
Thu Aug 8 00:11:50 UTC 2019

On 8/08/2019 9:04 am, Mikhailo Seledtsov wrote:
> Hi Severin, Bob,
>    Thank you for reviewing the code.
> On 8/7/19, 11:38 AM, Bob Vandette wrote:
>> Can’t you come up with a better way of synchronizing the test by 
>> possibly writing a
>> file and waiting for it to exist with a timeout?
> I will try out this approach.

This seems like a fundamental problem with jcmd - so cc'ing 

But I'm pretty sure they recently addressed a similar issue with the 
premature sending of the attach signal?


> Thanks,
> Misha
>> Isn’t there a shared volume between the two
>> processes?
>> We’ve been fighting test reliability for a while now.  I can only hope 
>> we’re getting
>> to the end.
>> Bob.
>>> On Aug 7, 2019, at 2:18 PM, Severin Gehwolf<sgehwolf at redhat.com>  wrote:
>>> Hi Misha,
>>> On Tue, 2019-08-06 at 20:17 -0700, mikhailo.seledtsov at oracle.com wrote:
>>>> Please review this change that fixes a container test 
>>>> TestJcmdWithSideCar.
>>>> My investigation indicated that a root cause for this failure is:
>>>> JCMD -l shows 'Unknown' for class name because the main class has not
>>>> been loaded yet.
>>>> The target test JVM has started, it is initializing, but has not loaded
>>>> the main test class.
>>> That's what I've found too.
>>>> The proposed solution is to try 'jcmd -l' several times, with a short
>>>> sleep in between.
>>> Thread.sleep() isn't great, but I'm not sure there is an alternative.
>>>> Also I have commented out the testCase02() due to another bug:
>>>> "JDK-8228850: jhsdb jinfo fails with ClassCastException:
>>>> s.j.h.oops.TypeArray cannot be cast to s.j.h.oops.Instance",
>>>> which is not a test bug. IMO, it is better to run the test and skip a
>>>> sub-case than to skip the entire test.
>>>>      JBS: https://bugs.openjdk.java.net/browse/JDK-8228960
>>>>      Webrev: http://cr.openjdk.java.net/~mseledtsov/8228960.00/
>>> Looks OK to me.
>>> Thanks,
>>> Severin

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