ExifInterface returns 0

I'm trying to get the image orientation using ExifInterface class but i always get 0.

Snippet:

ExifInterface ei;

try {
    ei = new ExifInterface("/storage/sdcard0/etp_images/31_demo2@gmail.com.jpg");
    int orientation = ei.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);

    Log.v("ORIENTATION", String.valueOf(orientation));

} catch (IOException e) {
    e.printStackTrace();
}

I was looking many answers about this question but none has result me. Thanks in advance.