Change
FileInputStream Fin=new FileInputStream(Environment.DIRECTORY_DOWNLOADS+"upload");
to
FileInputStream Fin=new FileInputStream(new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS), "upload"));
You should use Environment.getExternalStoragePublicDirectory
to get the path.
Or if you like more,
FileInputStream Fin=new FileInputStream(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS) + "/upload");
Change
r.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, "upload");
too with
r.setDestinationInExternalPublicDir(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS), "upload");