private void clobberThread(Thread t) {
    if (t == null) {
      return;
    }
    if (t.isAlive()) {
      logger.warn("Forcing thread stop on < {} >", t);

      // Start by being nice.
      t.interrupt();

      // we could be more violent here...
      // t.stop();
      try {
        for (int i = 0; i < MAX_STOP_ATTEMPTS && t.isAlive(); i++) {
          t.join(ClusterOperationExecutors.STOP_PAUSE_TIME);
          t.interrupt();
        }
      } catch (InterruptedException ex) {
        logger.debug("Interrupted while attempting to terminate threads.");
        Thread.currentThread().interrupt();
        // just keep going
      }

      if (t.isAlive()) {
        logger.warn("Thread refused to die: {}", t);
      }
    }
  }
Cheap tool to kill a referenced thread

@param t the thread to kill
geode-core/src/main/java/org/apache/geode/distributed/internal/ClusterDistributionManager.java