RFR 8071641: java/lang/management/ThreadMXBean/SynchronizationStatistics.java intermittently failed with NPE

[Daniel Fuchs]

Hi Jaroslav,

The only thread state that this test is waiting on seems to be 
Thread.State.BLOCKED - which makes me wonder if you could add a
method:

String waitForBlockedState(Thread t) throws InterruptedException {
    long tid = lt.getId();
    ThreadInfo ti;
    while ( (ti = mbean.getThreadInfo(tid)).getThreadState() != 
Thread.State.BLOCKED) {
       Thread.sleep(3);
    }
    return ti.getLockName();
}

Would that be feasible - or would it have side effects on what the
test is testing?

best regards,

-- daniel

On 29/01/15 14:03, Jaroslav Bachorik wrote:
> Please, review the following test change.
>
> Issue : https://bugs.openjdk.java.net/browse/JDK-8071641
> Webrev: http://cr.openjdk.java.net/~jbachorik/8071641/webrev.00/
>
> The test fails very intermittently with NPE. This seems to be caused by
> a data race between Thread.getStatus() and ThreadMXBean.getThreadInfo()
> - thread state is reported as BLOCKED but the ThreadInfo still contains
> a stale information (lockname == null).
>
> The solution would be re-retrieving the ThreadInfo until it reflects the
> actual thread state.
>
> -JB-