Async uploading an image as file to the server from Android application

HttpUploadImageTask.java

private class HttpUploadImageTask extends AsyncTask<String, Void, Boolean> {
    final Bitmap imageBitmap;
    public HttpUploadImageTask(final Bitmap imageBitmap) {
        this.imageBitmap = imageBitmap;
    }

    @Override
    protected Boolean doInBackground(String... urls) {
        for (final String u : urls) {
            try {
                process(new URL(u));
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return true;
    }

    private void process(final URL url) throws IOException {
        final String lineEnd = "\r\n";
        final String twoHyphens = "--";
        final String boundary = "*****";
        final String filename = "unnamed";
        final HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setDoInput(true);
        connection.setDoOutput(true);
        connection.setUseCaches(false);
        connection.setRequestMethod("POST");
        connection.setRequestProperty("Connection", "Keep-Alive");
        connection.setRequestProperty("ENCTYPE", "multipart/form-data");
        connection.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary);
        connection.setRequestProperty("uploaded_file", filename);
        final DataOutputStream out = new DataOutputStream(connection.getOutputStream());
        out.writeBytes(twoHyphens + boundary + lineEnd);
        out.writeBytes("Content-Disposition: form-data; name=\"uploaded_file\";filename=\""
                + filename + "\"" + lineEnd);
        out.writeBytes(lineEnd);
        imageBitmap.compress(Bitmap.CompressFormat.JPEG, 80, out);
        out.writeBytes(lineEnd);
        out.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);
        final int serverResponseCode = connection.getResponseCode();
        String serverResponseMessage = connection.getResponseMessage();
        Log.i("uploadImage", "HTTP Response is : "
                + serverResponseMessage + ": " + serverResponseCode);
        out.flush();
        out.close();
    }

    @Override
    protected void onPostExecute(Boolean result) {
        Log.i("uploadImage", "OK");
    }
}