code: public synchronized MucCreateConfigFormHandle createOrJoin(Resourcepart nickname) throws NoResponseException, XMPPErrorException,
                      InterruptedException, MucAlreadyJoinedException, NotConnectedException, NotAMucServiceException {
          MucEnterConfiguration mucEnterConfiguration = getEnterConfigurationBuilder(nickname).build();
          return createOrJoin(mucEnterConfiguration);
      }
docs: Create or join the MUC room with the given nickname.
  
  @param nickname the nickname to use in the MUC room.
  @return A {@link MucCreateConfigFormHandle} if the room was created while joining, or {@code null} if the room was just joined.
  @throws NoResponseException
  @throws XMPPErrorException
  @throws InterruptedException
  @throws NotConnectedException
  @throws MucAlreadyJoinedException
  @throws NotAMucServiceException