// (C) Insert data

        Scanner kbd = new Scanner(System.in);

        String userColour = "";
        int userLength;

        PreparedStatement preStatement = con.prepareStatement("INSERT INTO tblPencils (colour,length) values (?, ?)");

        while (true) {
            try {
                System.out.println("Enter your colour: (0 to exit)");
                userColour = kbd.next();

                if (userColour.equals("0")) {
                    break;
                }

                System.out.println("Enter your length");
                userLength = kbd.nextInt();

                preStatement.setString(1, userColour);
                preStatement.setInt(2, userLength);
                preStatement.executeUpdate();

            } catch (Exception ex) {
                System.out.println(ex);
            }
        }