code: public synchronized void close() {
      if (zooKeeper != null) {
        try {
          zooKeeper.close();
        } catch (InterruptedException e) {
          Thread.currentThread().interrupt();
          LOG.warning("Interrupted trying to close zooKeeper");
        } finally {
          zooKeeper = null;
          sessionState = null;
        }
      }
    }
docs: Closes the current connection if any expiring the current ZooKeeper session.  Any subsequent
  calls to this method will no-op until the next successful {@link #get}.