public static String userClassToString(byte[] buf) {
        if (buf == null) {
            return null;
        }
        
        List list = userClassToList(buf);
        Iterator it = list.iterator();
        StringBuffer s = new StringBuffer();
        
        while (it.hasNext()) {
            s.append('"').append((String) it.next()).append('"');
            if (it.hasNext()) {
                s.append(',');
            }
        }
        return s.toString();
    }