[Java]JProgressbar ne s'affichant pas

       
       progressBar.setVisible(true);
        progressBar.setValue(0);
        progressBar.setIndeterminate(false);
        progressBar.setMinimum(0);
        progressBar.setMaximum(100);

        progressBar.paint(progressBar.getGraphics());

 private void pipe(InputStream in, OutputStream out) throws IOException {
        byte[] buf = new byte[10000];
        int nread;

        synchronized (in) {
            double done;
            double delta;

            while ((nread = in.read(buf, 0, buf.length)) >= 0) {
                out.write(buf, 0, nread);
                transfered += nread;

                delta = (double) (getFileLength() - getTransfered()) / getFileLength();
                done = (100 * (1 - delta));
                if(done%5 != 0) continue;
                progressBar.setValue((int) done);
                progressBar.getTopLevelAncestor().paint(progressBar.getGraphics());
            }
        }
        out.flush();
    }

Configuration: Linux Debian
Mozilla 1.8.1.2