static Map<Class, HashMap<S, Method>> callOpt_noArgs_cache = newDangerousWeakHashMap();

static O callOpt_noArgs(O o, S method) ctex {
  if (o == null) ret null;
  if (o instanceof Class)
    ret callOpt(o, method); // not optimized
  
  Class c = o.getClass();
  HashMap<S, Method> map;
  synchronized(callOpt_noArgs_cache) {
    map = callOpt_noArgs_cache.get(c);
    if (map == null)
      map = callOpt_noArgs_makeCache(c);
  }

  Method m = map.get(method);
  ret m != null ? m.invoke(o) : null;
}

// used internally - we are in synchronized block
static HashMap<S, Method> callOpt_noArgs_makeCache(Class c) {
  new HashMap<S, Method> map;
  Class _c = c;
  do {
    for (Method m : c.getDeclaredMethods())
      if (m.getParameterTypes().length == 0 
        && !reflection_isForbiddenMethod(m)) {
        makeAccessible(m);
        S name = m.getName();
        if (!map.containsKey(name))
          map.put(name, m);
      }
    _c = _c.getSuperclass();
  } while (_c != null);
  callOpt_noArgs_cache.put(c, map);
  ret map;
}

Began life as a copy of #1001199