hashmap

@SuppressWarnings("unchecked")
    public static HashMap<String, Integer> readWarningsFile()
            throws ClassNotFoundException, IOException
    {
        try (ObjectInputStream is = new ObjectInputStream(new FileInputStream(PATH))) {
            return (HashMap<String, Integer>) is.readObject();
        }
    }

    public static void saveWarningsFile(HashMap<String, Integer> users)
            throws IOException
    {
        File f = new File(WHITELIST_PATH);
        f.mkdirs();
        if(!f.exists())
            f.createNewFile();

        try (ObjectOutputStream os = new ObjectOutputStream(new FileOutputStream(PATH))) {
            os.writeObject(users);
        }
    }