Created attachment 37703 [details]
example source file

Hi guys,

In the following example second invocation of Workbook.close() produces file test2.xlsx with two sheets, but the second has no data. 
Also observed: the first file has size of 32,952 bytes and the second one has 61,619 bytes.

      int rowNumber = 0;
      int cellNumber = 0;
      String outputFileName = "c:/temp/test1.xlsx";
      File outFile = new File(outputFileName);
      File outFile2 = new File("c:/temp/test2.xlsx");
      Workbook workbook = new SXSSFWorkbook(100);
      try {
         Sheet sheet = workbook.createSheet("Sheet1");
         Row row = null;
         for (int i = 0; i < 1000; i++) {
            row = sheet.createRow(rowNumber++);
            cellNumber = 0;
            for (int j = 1; j <= 10; j++) {
               Cell cell = row.createCell(cellNumber++);
               cell.setCellValue(String.valueOf(j));
            }
         }
         try (FileOutputStream out = new FileOutputStream(outFile)) {
            workbook.write(out);
         }
      } finally {
         workbook.close();
         ((SXSSFWorkbook) workbook).dispose();
      }

      workbook = new SXSSFWorkbook((XSSFWorkbook) WorkbookFactory.create(outFile), 100);
      try {
         Sheet sheet = workbook.createSheet("Sheet2");
         Row row = null;
         for (int i = 0; i < 1000; i++) {
            row = sheet.createRow(rowNumber++);
            cellNumber = 0;
            for (int j = 1; j <= 10; j++) {
               Cell cell = row.createCell(cellNumber++);
               cell.setCellValue(String.valueOf(j));
            }
         }
         try (FileOutputStream out = new FileOutputStream(outFile2)) {
            workbook.write(out);
         }
      } finally {
         workbook.close();
         ((SXSSFWorkbook) workbook).dispose();
      }