code: public static boolean check(Class<?> clz) {
          if (Config.CACHE_SEEN_CLASSES_V) {
              int index = hash(clz);
              if (CACHE[index] == clz) {
                  return true;
              }
              CACHE[index] = clz;
          }
          return false;
      }
docs: Checks if the given class is in cache. If not, puts the class in the
  cache and returns false; otherwise it returns true.
  
  @param clz
  Class object to search for in cache.
  @return true if the given argument is in cache, false otherwise.