How do i...solve this error in music player

Caused by: java.lang.NullPointerException: Attempt to get length of null array
                                                      at com.example.mahakal.musicplayer.SongsManager.getPlayList(SongsManager.java:25)

<pre>public ArrayList<HashMap<String, String>> getPlayList(){
        File home = new File(MEDIA_PATH);

        if (home.listFiles(new FileExtensionFilter()).length > 0) {
            for (File file : home.listFiles(new FileExtensionFilter())) {
                HashMap<String, String> song = new HashMap<String, String>();
                song.put("songTitle", file.getName().substring(0, (file.getName().length() - 4)));
                song.put("songPath", file.getPath());

                // Adding each song to SongList
                songsList.add(song);
            }
        }
        // return songs list array
        return songsList;
    }