code: @Override
    public synchronized void dispose() {
      if (saslServer != null) {
        try {
          saslServer.dispose();
        } catch (SaslException e) {
          // ignore
        } finally {
          saslServer = null;
        }
      }
    }
docs: Disposes of any system resources or security-sensitive information the
  SaslServer might be using.