});
//backend.addListener(MessageListener.class, this);
backend.addExtensionHandler("http://jabber.org/protocol/muc#user",
new XMUCUserHandler());
backend.addExtensionHandler("http://jabber.org/protocol/muc#owner",
new XMUCOwnerHandler());
backend.addExtensionHandler("http://jabber.org/protocol/muc#admin",
new XMUCAdminHandler());
backend.addExtensionHandler("jabber:x:conference",
new XConferenceHandler());
groupchatWindows = new GroupChatWindows(backend);