code: static void register(MetaBean metaBean) {
          Class<? extends Bean> type = metaBean.beanType();
          if (META_BEANS.putIfAbsent(type, metaBean) != null) {
              throw new IllegalArgumentException("Cannot register class twice: " + type.getName());
          }
      }
docs: Registers a meta-bean.
  <p>
  This should be done for all beans in a static factory where possible.
  If the meta-bean is dynamic, this method should not be called.
  
  @param metaBean  the meta-bean, not null
  @throws IllegalArgumentException if unable to register