code: public List<DomainBareJid> getMucServiceDomains() throws NoResponseException, XMPPErrorException, NotConnectedException, InterruptedException {
          return serviceDiscoveryManager.findServices(MUCInitialPresence.NAMESPACE, false, false);
      }
docs: Returns a collection with the XMPP addresses of the Multi-User Chat services.
  
  @return a collection with the XMPP addresses of the Multi-User Chat services.
  @throws XMPPErrorException
  @throws NoResponseException
  @throws NotConnectedException
  @throws InterruptedException