code: public synchronized MultiUserChatLight getMultiUserChatLight(EntityBareJid jid) {
          WeakReference<MultiUserChatLight> weakRefMultiUserChat = multiUserChatLights.get(jid);
          if (weakRefMultiUserChat == null) {
              return createNewMucLightAndAddToMap(jid);
          }
          MultiUserChatLight multiUserChatLight = weakRefMultiUserChat.get();
          if (multiUserChatLight == null) {
              return createNewMucLightAndAddToMap(jid);
          }
          return multiUserChatLight;
      }
docs: Obtain the MUC Light.
  
  @param jid
  @return the MUCLight.