code: static void shutdown() {
          synchronized (lock) {
              switch (state) {
              case RUNNING:       /* Initiate shutdown */
                  state = HOOKS;
                  break;
              case HOOKS:         /* Stall and then return */
              case FINALIZERS:
                  break;
              }
          }
          synchronized (Shutdown.class) {
              sequence();
          }
      }
docs: /* Invoked by the JNI DestroyJavaVM procedure when the last non-daemon
  thread has finished.  Unlike the exit method, this method does not
  actually halt the VM.