if (advisory.getExpires().after(currentDate)) {
if (advisory.getExpires() == null || advisory.getExpires().after(currentDate)) {
    public List<Advisory> getAdvisories() {        Date currentDate = Calendar.getInstance().getTime();        List<Advisory> result = new ArrayList<Advisory>();        for (Advisory advisory : super.getAdvisories()) {            if (advisory.getExpires().after(currentDate)) {                result.add(advisory);            }        }        return result;    }