Java Development Tools

I have an ADF Table in JSF page that is bounded to View Object which holds user's uploaded files. This View Object contains all the information needed to download a file like blob domain , file type and file name. For each row there is a download button that enables the user to download the selected file. 

Every things works perfectly for the first time. Problem is when the user press the download button for some file he/she already download it, the file get corrupted. The file appears in the download section for browser, but when I tried to open it tells that the file can not be open because the file format or file extension is not supported.

I am using Jdeveloper 11.1.2.3 with ADF Technology

here is the button in the JSF page:

<af:column id="c31">
<af:commandButton text="Download" id="cb12" partialSubmit="true">
   <af:fileDownloadActionListener method="#{ITDetalisBean.downloadSelectedFile}"
  filename="#{row.FileName}" contentType="#{row.FileType}"/>
</af:commandButton>
</af:column>

As you can see the button is placed in <af:column> tag. So for each file row there is corresponding download button.

Here is the Bean method:

  public void downloadSelectedFile(FacesContext facesContext, OutputStream outputStream) 
{
   // get the view object from the application module
   AppModuleImpl appM = (AppModuleImpl)(JSFUtils.getApplicationModule("AppModuleDataControl"));
   ViewObject fileUploadedVO = appM.findViewObject("UplodedFilesViewTransient1");

   // get the file content as blob domain from the current row
   BlobDomain blobDomain=(BlobDomain)fileUploadedVO.getCurrentRow().getAttribute("FileContn");


   // download the file using output stream
   try {
   HttpServletResponse response =
   (HttpServletResponse)FacesContext.getCurrentInstance().getExternalContext().getResponse();

   InputStream in = blobDomain.getBinaryStream();
  outputStream = response.getOutputStream();

   byte[] buf = new byte[1024];
   int count;
   while ((count = in.read(buf)) >= 0) {
  outputStream.write(buf, 0, count);
   }

  in.close();
  outputStream.flush();
  outputStream.close();
  facesContext.responseComplete();


   } catch (IOException ex) {
   System.out.println(ex.getMessage());
  ex.printStackTrace();
   } catch (Exception e) {
   System.out.println(e.getMessage());
  e.printStackTrace();
   }
}