private void cleanTransferHistory() {
    PreparedStatement preparedStatement = null;

    Connection connection = null;
    try {

      connection = dataSource.getConnection();

      connection.setAutoCommit(false);

      preparedStatement = connection.prepareStatement("DELETE FROM TransferHistory");

      preparedStatement.executeUpdate();
      preparedStatement =
          connection.prepareStatement("ALTER TABLE TransferHistory AUTO_INCREMENT = 1");

      preparedStatement.executeUpdate();

    } catch (SQLException e) {
      e.printStackTrace();
    } finally {
      try {
        if (connection != null) {
          connection.setAutoCommit(true);
        }
        if (preparedStatement != null) {
          preparedStatement.close();
        }
      } catch (SQLException e) {
        e.printStackTrace();
      }
    }

    cleanSession();
  }
  private void cleanSession() {
    PreparedStatement preparedStatement = null;

    try {

      preparedStatement = dataSource.getConnection().prepareStatement("DELETE FROM Session");

      preparedStatement.executeUpdate();

    } catch (SQLException e) {
      e.printStackTrace();
    } finally {
      try {
        if (preparedStatement != null) {
          preparedStatement.close();
        }
      } catch (SQLException e) {
        e.printStackTrace();
      }
    }

    cleanUsers();
  }