public static List<Message> getMessagesByUser(User user) {

    List<Message> messages = new ArrayList<Message>();
    ResultSet resultSet;
    Message message;
    String text, hash;
    int id;
    boolean valid = true;

    String sql = "SELECT * FROM mail WHERE userid = " + user.getId() + " ;";

    try {
      resultSet = getStatement().executeQuery(sql);

      while (resultSet.next()) {
        id = resultSet.getInt("mailid");
        text = resultSet.getString("message");
        hash = resultSet.getString("hash");
        message = Message.create(id, text, text.length(), hash, valid);
        messages.add(message);
      }

      getStatement().close();

    } catch (SQLException e) {
      e.printStackTrace(); // To change body of catch statement use File | Settings | File
      // Templates.
    }

    return messages;
  }
  @Deprecated
  public static void addNewMessageToUser(User user, Message message) {

    String sql = "SELECT MAX(mailid) as 'maxid' FROM mail;";

    ResultSet resultSet = null;
    int number = 10000;

    try {
      resultSet = getStatement().executeQuery(sql);

      resultSet.next();
      number = resultSet.getInt("maxid");

      number++;
      sql =
          "INSERT INTO mail (mailid,userid,hash,message) values("
              + number
              + ","
              + user.getId()
              + ",'"
              + message.getHash()
              + "','"
              + message.getContent().replace("'", "\"")
              + "');";

      getStatement().execute(sql);

      resultSet.close();
      getStatement().close();

    } catch (SQLException e) {
      e.printStackTrace();
    }
  }
  public static void saveMail(User user, Message message) {

    ResultSet resultSet = null;

    try {

      String sql =
          "INSERT INTO mail (mailid,userid,hash,message) values("
              + message.getId()
              + ","
              + user.getId()
              + ",'"
              + message.getHash()
              + "','"
              + message.getContent()
              + "');";

      getStatement().execute(sql);

      resultSet.close();
      getStatement().close();

    } catch (SQLException e) {
      e.printStackTrace();
    }
  }
 public static void addMessagesToUser(User user) {
   List<Message> messages = MailProvider.getMessagesByUser(user);
   user.setUserMails(messages);
 }