New to Java

i want to write on "Double Order" column after check the "Order ID" column wheter it's double value or not. i use apache poi. can someone help me?

public static void main(String[] args) throws IOException {

            FileInputStream file = new FileInputStream(new File(

                    "C:\\Users\\Ricky\\Desktop\\Double Booking1.xlsx"));

            XSSFWorkbook workbook = new XSSFWorkbook(file);

          XSSFSheet sheet = workbook.getSheetAt(0);

            Iterator<Row> rowIterator = sheet.iterator();

            while (rowIterator.hasNext()) {

                Row row = rowIterator.next();

                Iterator<Cell> cellIterator = row.cellIterator();

                while (cellIterator.hasNext()) {

                    Cell cell = cellIterator.next();

                    if(cell.getColumnIndex()==1) {

                    }

                    System.out.print(cell.toString() + "  ");

                }

                System.out.println();

            }

    }