The file format and extension of .xls don't match -- apache-poi 4.1.2

Question

I am creating xls with apache-poi version 4.1.2. when I do with junit it is working correctly but if I use tomee with container then the generated file is showing an error like

The file format and extension of <filename>.xls don't match

• Java version 1.8

• tomee-plus 1.7.5

• K8s docker container

• Using HSSFWorkbook

  File outputFile = new File(dir, fileParameter.getFileName()); if (outputFile.exists() && !FileUtils.deleteFile(outputFile)) { LOG.warn("Cannot delete"); } try (final HSSFWorkbook workbook = new HSSFWorkbook()) { final HSSFSheet sheet = workbook.createSheet(SUMMARY_SHEET_NAME); //Header Row int rowNum = 0; int cellNum = 0; HSSFRow row = sheet.createRow(rowNum++); row.createCell(cellNum++).setCellValue("TEST1"); row.createCell(cellNum++).setCellValue("TEST2"); row.createCell(cellNum++).setCellValue("TEST3"); row.createCell(cellNum++).setCellValue("TEST4"); row.createCell(cellNum++).setCellValue("TEST5");

    try (FileOutputStream fileOutputStream = new FileOutputStream(outputFile)) {
        workbook.write(fileOutputStream);
    }
  

  }