code: private static boolean canBulkLoad(AsyncCacheLoader<?, ?> loader) {
      try {
        Class<?> defaultLoaderClass = AsyncCacheLoader.class;
        if (loader instanceof CacheLoader<?, ?>) {
          defaultLoaderClass = CacheLoader.class;
  
          Method classLoadAll = loader.getClass().getMethod("loadAll", Iterable.class);
          Method defaultLoadAll = CacheLoader.class.getMethod("loadAll", Iterable.class);
          if (!classLoadAll.equals(defaultLoadAll)) {
            return true;
          }
        }
  
        Method classAsyncLoadAll = loader.getClass().getMethod(
            "asyncLoadAll", Iterable.class, Executor.class);
        Method defaultAsyncLoadAll = defaultLoaderClass.getMethod(
            "asyncLoadAll", Iterable.class, Executor.class);
        return !classAsyncLoadAll.equals(defaultAsyncLoadAll);
      } catch (NoSuchMethodException | SecurityException e) {
        logger.log(Level.WARNING, "Cannot determine if CacheLoader can bulk load", e);
        return false;
      }
    }
docs: Returns whether the supplied cache loader has bulk load functionality.