Integer roomnum = Integer.parseInt(textField.getText());
SQLQuery bu = new BookUpdate(null, textArea);
List<Object> args = new LinkedList<Object>();
args.add(id); args.add(roomnum);
bu.prepareQuery(args);
bu.doQuery();
} catch (NumberFormatException e) {
textArea.appendText("invalid room number");
} catch (SQLException e) {
e.printStackTrace();
}