JVMTI is an optional technology used for debugging, profiling, monitoring etc.

In JDK 8 b129 JVMTI works under plugin on all OSes, but MacOS (checked 10.9). It also works on MacOS in the configuration without plugin. 7u55 also works with and without plugin.

On the very same machine JDWP works under plugin with both JDK 8 b129 and JDK 7u55 b09.