Sonatype Lift raised a THREAD_SAFETY_VIOLATION in ManagedProcess#assertWaitForIsValid() :

THREAD_SAFETY_VIOLATION: Read/Write race. Non-private method ManagedProcess.assertWaitForIsValid() indirectly reads without synchronization from this.isAlive. Potentially races with write in method ManagedProcess.startExecute().
Reporting because another access to the same memory occurs on a background thread, although this access may not.

@cardamon is this the sort of thing you would enjoy contributing a fix for?

I'm hesitant whether or not to already merge your PR #96 as-is. Thoughts?