--- a/hotspot/src/share/vm/runtime/thread.hpp	Wed May 11 00:40:59 2016 +0000
+++ b/hotspot/src/share/vm/runtime/thread.hpp	Wed May 11 01:02:28 2016 -0400
@@ -96,6 +96,7 @@
 //       - GangWorker
 //       - GCTaskThread
 //   - JavaThread
+//     - various subclasses eg CompilerThread, ServiceThread
 //   - WatcherThread
 
 class Thread: public ThreadShadow {
@@ -314,8 +315,7 @@
 
   // Manage Thread::current()
   void initialize_thread_current();
-  private:
-  void clear_thread_current(); // needed for detaching JNI threads
+  void clear_thread_current(); // TLS cleanup needed before threads terminate
 
   public:
   // thread entry point
@@ -743,6 +743,11 @@
   // Constructor
   WatcherThread();
 
+  // No destruction allowed
+  ~WatcherThread() {
+    guarantee(false, "WatcherThread deletion must fix the race with VM termination");
+  }
+
   // Tester
   bool is_Watcher_thread() const                 { return true; }