static Map<S, Class> classForNameOpt_cache = synchroHashMap();

static Class classForNameOpt(S name) ctex {
  if (classForNameOpt_cache.containsKey(name))
    ret classForNameOpt_cache.get(name);
  Class c = null;
  try { c = Class.forName(name); } catch {}
  classForNameOpt_cache.put(name, c);
  ret c;
}