The Unsafe monitor methods have been removed in JDK 9. They should be marked as deprecated in an 8u release.
Suggested release note text:
The methods monitorEnter, monitorExit and tryMonitorEnter on sun.misc.Unsafe are marked as deprecated in JDK 8u60 and will be removed in JDK 9. These methods are not used within the JDK itself and are very rarely used outside of the JDK.