private UsersReader() throws IOException {
		try {
			FileInputStream fin = new FileInputStream(MAP_DIR);
			ObjectInputStream oos = new ObjectInputStream(fin);
			userMap = (HashMap<Long, Integer>) oos.readObject();
			oos.close();
		} catch (Exception e) {
			e.printStackTrace();
		}

		tr = new TreeMap<Integer, UserData>();
		FileInputStream fin = new FileInputStream("UserObjects");
		ObjectInputStream ois = new ObjectInputStream(fin);
		while (true) {
			try {
				UserData s = (UserData) ois.readObject();
				if (userMap.containsKey(s.id))
					tr.put(userMap.get(s.id), s);
			} catch (Exception e) {
				fin.close();
				ois.close();
				break;
			}
		}
		System.out.println("total users in users map tree "+tr.size());
	}