code: public static ConstructorMetadata introspect(Class<?> clazz) {
      ConstructorMetadata metadata = cache.get(clazz);
      if (metadata != null) {
        return metadata;
      }
      return loadMetadata(clazz);
    }
docs: Introspects the given Persistence class and returns the {@link ConstructorMetadata}.
  
  @param clazz
  the class to introspect
  @return the {@link ConstructorMetadata}.