codice:
try {
  MySqlDataSource dataSource = new MySqlDataSource();
  Connection conn = dataSource.getConnection();
  Statement st = conn.createStatement();
  ResultSet rs = st.executeQuery(query1);
  while (rs.next()) {
    rs.getString(1);
  }
  rs.close();
  rs = st.executeQuery(query2);
  while (rs.next()) {
    rs.getString(1);
  }
  int rowsUpdated = st.executeUpdate(update);
  conn.commit();
}
catch (SQLException sqlex) {
  conn.rollback();
}