Fix for possible NPE
Merge branch 'master' into unstable_staging
Revert "Don't need to synchronize here, we can just park and unpark"

This reverts commit 68d812b033723ef006b110825427761e52df2aa5.

Although I think this idea is sound, there is something that is not quite working right.
Call UncaughtExceptionHandler here as well
Merge branch 'master' into unstable_staging