public static ArrayList<BillItem> listBillItems(int billID) {

        String query = "SELECT *"
                + "FROM `billItem`"
                + "WHERE `billItem`.`billId` = '%d';";

        ArrayList<BillItem> listOfBillItems = new ArrayList<>();
        DBA dba = Helper.getDBA();
        try {
            ResultSet rs = dba.executeQuery(String.format(query, billID));

            if (rs != null) {

                while (rs.next()) {
                    BillItem newBillItem = new BillItem();

                    newBillItem.setBillId(rs.getInt("billId"));
                    newBillItem.setMedicineId(rs.getInt("medicineId"));
                    newBillItem.setQuanitity(rs.getInt("quantity"));

                    listOfBillItems.add(newBillItem);
                }
                rs.close();
                dba.closeConnections();
            }
        } catch (SQLException sqlEx) {
            dba.closeConnections();
            Helper.logException(sqlEx);
        }

        return listOfBillItems;
    }