Trying to load json from assets in android studio

Here is my code:

    public String loadJSONFromAsset() {
    String json = null;
    try {

        InputStream is = getAssets().open("index.json");

        int size = is.available();

        byte[] buffer = new byte[size];

        is.read(buffer);

        is.close();

        json = new String(buffer, "UTF-8");


    } catch (IOException ex) {
        ex.printStackTrace();
        return null;
    }
    return json;

}

JSONObject object = new JSONObject(loadJSONFromAsset());

I get an error underlining the last row(JSONObject object = new JSONObject(loadJSONFromAsset());), saying Unhandled Exception org.json.JSONException