code: public void unblockRoom(DomainBareJid mucLightService, Jid roomJid)
              throws NoResponseException, XMPPErrorException, NotConnectedException, InterruptedException {
          HashMap<Jid, Boolean> rooms = new HashMap<>();
          rooms.put(roomJid, true);
          sendUnblockRooms(mucLightService, rooms);
      }
docs: Unblock a room.
  
  @param mucLightService
  @param roomJid
  @throws NoResponseException
  @throws XMPPErrorException
  @throws NotConnectedException
  @throws InterruptedException