title: Overwriting an excel file using Java POI
body: <p>I am new to Java POI and i am trying to overwrite an excel file using Java POI.Let me make it clear, i don't want to open a new .xls file every time time i build the code however the code i wrote does it that way.The purpose for this is to, i will build the chart on excel and read the values for the chart from the database and write it to the excel file by using Java POI.Here is my code:  </p>
  
  <pre><code>HSSFWorkbook workbook = new HSSFWorkbook();
  HSSFSheet firstSheet = workbook.createSheet("oldu");
  HSSFSheet secondSheet = workbook.createSheet("oldu2");
  
  HSSFRow rowA = firstSheet.createRow(6);
  HSSFCell cellA = rowA.createCell(3);
  cellA.setCellValue(new HSSFRichTextString("100"));
  cellA.setCellValue(100);
  
  HSSFRow rowB = secondSheet.createRow(0);
  HSSFCell cellB = rowB.createCell(0);
  cellB.setCellValue(new HSSFRichTextString("200"));
  
  FileOutputStream fos = null;
  try {
      fos = new FileOutputStream(new File("CreateExcelDemo.xls"));
      workbook.write(fos);
  } catch (IOException e) {
      e.printStackTrace();
  } finally {
      if (fos != null) {
          try {
              fos.flush();
              fos.close();
          } catch (IOException e) {
              e.printStackTrace();
          }
      }
  }
  </code></pre>