Hi,

The nullSafeGet doesn't protect from nulls because 

String value = resultSet.getString(names[0]); can return null.

I've changed nullSafeGet to:
    public Object nullSafeGet(ResultSet resultSet, String[] names,
Object owner)
            throws HibernateException, SQLException {
        if (resultSet.wasNull()) return null;
        String value = resultSet.getString(names[0]);
        if (value == null) return null;
        return getObject(value);
    }