This is a seemingly pointless change. The RW-lock code is 100%
correct (afaict), yet we've seen repeated cases of test runs
hanging in JMX query because this lock is seemingly left held
by what seems to be the reaper task.
There is no explanation for this, no sign of exceptions/errors
that could explain the lock being broken. Nor any known JDK/JVM
bugs.
Yet, in tests, it seems that replacing the lock with a more
coarse, yet proven, synchronized, fixes the issue. So there.
I officially hate this patch, and it should not exist.
c2fc96be71