code: public boolean isServiceEnabled(Jid user) throws NoResponseException, XMPPErrorException, NotConnectedException, InterruptedException {
          return serviceDiscoveryManager.supportsFeature(user, MUCInitialPresence.NAMESPACE);
      }
docs: Returns true if the specified user supports the Multi-User Chat protocol.
  
  @param user the user to check. A fully qualified xmpp ID, e.g. jdoe@example.com.
  @return a boolean indicating whether the specified user supports the MUC protocol.
  @throws XMPPErrorException
  @throws NoResponseException
  @throws NotConnectedException
  @throws InterruptedException