MediaDescriptionCompat.getMediaId() on a null object reference

Question

Currently playing media song using .playFromMediaId like this

if (mMediaBrowser.isConnected()) {
                MediaControllerCompat.getMediaController(PlaybackActivity.this).getTransportControls()
                        .playFromMediaId(song.getMediaId(), null);

            }

Now got the new requirement to play Radio URL instead of media file / song, so I am playing using .playFromUri like this

MediaControllerCompat.getMediaController(PlaybackActivity.this).getTransportControls()
                         .playFromUri(Uri.parse("http://bbcmedia.ic.llnwd.net/stream/bbcmedia_radio1_mf_p"), null);

But always getting Exception:

java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.support.v4.media.MediaDescriptionCompat.getMediaId()' on a null object reference

Method where I am getting exception

public Song getCurrentPlayingSong() {

        try {

            for (Song song : LocalQueueManager.getInstance().getCurrentQueue()) {
                if (String.valueOf(song.getRandomMediaId()).equalsIgnoreCase(currentPlayingDescription.getMediaId())) { // Exception
                    return song;
                }
            }

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

        return null;
    }

So my question is what to use If I would like to play Radio URL instead Song