private String _answer(String objectId, String message) throws FacebookException {
        ensureAuthorizationEnabled();
        JSONObject json = post(buildEndpoint(objectId, "messages"),
                new HttpParameter[]{new HttpParameter("message", message)})
                .asJSONObject();
        try {
            return json.getString("id");
        } catch (JSONException jsone) {
            throw new FacebookException(jsone.getMessage(), jsone);
        }
    }