code: private static DomainBareJid getMultipleRecipientServiceAddress(XMPPConnection connection) throws NoResponseException, XMPPErrorException, NotConnectedException, InterruptedException {
          ServiceDiscoveryManager sdm = ServiceDiscoveryManager.getInstanceFor(connection);
          return sdm.findService(MultipleAddresses.NAMESPACE, true);
      }
docs: Returns the address of the multiple recipients service. To obtain such address service
  discovery is going to be used on the connected server and if none was found then another
  attempt will be tried on the server items. The discovered information is going to be
  cached for 24 hours.
  
  @param connection the connection to use for disco. The connected server is going to be
  queried.
  @return the address of the multiple recipients service or <tt>null</tt> if none was found.
  @throws NoResponseException if there was no response from the server.
  @throws XMPPErrorException
  @throws NotConnectedException
  @throws InterruptedException