public <Y extends Object> Y readFromSession(String key) {
        synchronized (THREAD_LOCK) {
            ConcurrentHashMap hashMap;
            Object temp = session.getAttribute(SESSION);
            if (temp != null && temp instanceof ConcurrentHashMap) {
                hashMap = (ConcurrentHashMap) temp;
            } else {
                return null;
            }
            temp = hashMap.get(key);
            if (temp == null) {
                return null;
            }else if (temp instanceof Y){ // HATA
                return (Y) temp;
            } else {
                throw new Exception();
            }
        }
    }