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

static Class classForName(S name, O classFinder default null) {
  // first clause is when we're in class init
  if (classForName_cache == null || classFinder != null)
    ret classForName_uncached(name, classFinder);
  Class c = classForName_cache.get(name);
  if (c == null)
    classForName_cache.put(name, c = classForName_uncached(name, null));
  ret c;
}

static Class classForName_uncached(S name, O classFinder) ctex {
  if (classFinder != null) ret (Class) callF(classFinder, name);
  ret Class.forName(name);
}