Analysis of the use of methods sun.misc.Unsafe.monitorEnter, monitorExit and tryMonitorEnter on jars in maven central indicates they are not widely used (mostly just one artifact and that is only required to work around a class loading issue on Java 6).
It is proposed these methods be removed. See the discussion on core-libs:
Preliminary patches are here:
Plus another that removes prefetch code that no longer appears to be used: