public static void send(String userName, String msg) {
        String all = "*";
        String user = userName;
        System.out.println(user);
        if (onlineUsers.containsKey(user)) {
            ClientHandler ch = onlineUsers.get(user);
            ch.send(ch, msg);
        }
        if (userName.equals(all)) {
            ArrayList<ClientHandler> as = new ArrayList<>();
            as.addAll(onlineUsers.values());

            for (int i = 0; i < as.size(); i++) {
                ClientHandler ch = as.get(i);
                ch.send(ch, msg);

            }
        }
    }