Excel Writer

public static void excelWriter (String file){
        try {
            FileInputStream fileInputStream = new FileInputStream(file);
            XSSFWorkbook workbook = new XSSFWorkbook(fileInputStream);
            XSSFSheet sheet = workbook.getSheetAt(0);

            for (int i = 0; i < letterCount[0].length; i++){

                Row row = sheet.createRow(i+1);
                Cell cell = row.createCell(0);
                cell.setCellValue(letterCount[0][i]);
                for (int j = 0; j < letterCount.length; j++){
                    cell = row.createCell(j+1);
                    cell.setCellValue(letterCount[j][i]);
                }
                fileInputStream.close();

                FileOutputStream fileOutputStream = new FileOutputStream(file);
                workbook.write(fileOutputStream);
                workbook.close();
                fileOutputStream.close();
            }
        } catch (Exception e){
            System.out.println(e.getMessage());

        }
    }