public void setAllowedForGuest(boolean b) {
public synchronized void setAllowedForGuest(boolean b) {
    public void setAllowedForGuest(boolean b) {        boolean old = this.isAllowedForGuest();        this.allowedForGuest = b;        if (old != b) {            if (old) {                Enumeration enum = this.getCurrentUserEnum();                User tmpUser;                while (enum.hasMoreElements()) {                    tmpUser = (User)enum.nextElement();                    if (tmpUser.isGuest()) {                        tmpUser.removeFromAllowedChannelList(this);                        tmpUser.setCurrentChannel(null);                    }                }            }        }