If there is no thread awareness, you cannot safely stop/suspend/resume a thread in general
. Depending on your current situation, this may or may not matter (though, it sounds like from your situation you might not have this luxury and will need to safely remove any object locks that thread is holding).
If you want more information about the problems associated with stop/suspend/resume, see this page: Java Thread Primitive Depracation
. They also suggest some alternatives to using these methods, but they are all similar to what we have provided as alternatives here.