public void processPacket(Packet packet) {
JID fromJID = new JID(packet.getFrom());
log.debug("Inv" + Utils.prefix(fromJID) + ": Received userList");
UserListInfo userListInfo = userListExtProv.getPayload(packet);
if (userListInfo == null) {
log.warn("Inv" + Utils.prefix(fromJID)
+ ": The received userList packet's"
+ " payload is null.");