@Override
    public String toJSONString() {
        Gson gson = new GsonBuilder()
                .excludeFieldsWithoutExposeAnnotation()
                //.registerTypeAdapter(Date.class, new DateSerializer())
                //.setDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'")
                .create();
        return gson.toJson(this);
    }
@ Override public String toJSONString ( ) { Gson gson = new GsonBuilder ( ) . excludeFieldsWithoutExposeAnnotation ( ) . create ( ) ; return gson . toJson ( this ) ; }
Creates the JSON representation of an Item