[Verifying Downloads] Java-Downloaded file not same filesize as on server

Question

This is in the security forum, but really involves a few details:
1.) My program downloads files from a server
2.) I have precalculated hash md5 values and file sizes in a .cfg file in the server which is also downloaded
3.) The md5 is calculated of the downloaded files
4.) The filesize is checked and the md5s are checked
I have 4 client windows computers I've tested this on. It worked on 3. The fourth has a strange behavior: About every other file would have ~ 8 additional bytes in the filesize. I have no idea where those bytes are coming from, everytime it redownloads, same filesize, albeit 8 bytes too big. Therefore, the Md5 is screwed up.
Here's my downloading from server code:
OutputStream out = null;
          InputStream  in = null;
          try {
               URLConnection dat = online.openConnection();
               local.getParentFile().mkdirs();
               out = new FileOutputStream(local);
               while(true){
                    try {
                         in = dat.getInputStream();
                         break;
                    } catch (ConnectException e){
                         System.err.println("Couldn't contact server!");
               byte[] buffer = new byte[1024];
               int numRead;
               tsecago = System.nanoTime();
               readbytessecAgo = -1;
               while ((numRead = in.read(buffer)) != -1) {
                    out.write(buffer, 0, numRead);
                    readbytes += numRead;
          } catch (Exception e){
               e.printStackTrace();
          } finally {
               try {
                    if (in != null) {
                         in.close();
                    if (out != null) {
                         out.close();
               } catch (IOException ioe) {
          }SO, my solution was as follows:
1.) Download file once and check md5 & filesize
2.) If failed, download file AGAIN and check md5 & filesize
3.) If failed 2x, download file for last time and check filesize - if the filesize is within 40 bytes of the actual file, allow it.
This now works on all 4 computers, and as far as I can tell the downloaded files are wholly correct.
But this is really annoying! Why is the above download code producing 8 extra bytes?!

Answer 1

Thanks for your reply, Timo, and John, the same file downloading is working fine with my Integrated weblogic server, but the same application when i deployed in my DEV server i am getting the error.
Code which i am trying to download file is
public void downloadCardInserts(FacesContext facesContext,
OutputStream outputStream) throws FileNotFoundException,
IOException {
// Add event code here...
UploadedFile filename=(UploadedFile)browseFile.getValue();
String fname=filename.getFilename();
String fname1="//bwi-wfp-v01/Apps/SCII/TEST/LOG/Cards/RENEWAL/"+fname;
System.out.println("file name11111:"+fname1);
FileInputStream in = new FileInputStream(new File(fname1));
byte[] buffer = new byte[1024];
int bytes = in.read(buffer);
while (bytes >= 0) {
outputStream.write(buffer, 0, bytes);
bytes = in.read(buffer);
}