code: private void pushUIComponentClassicTagBase() {
  
          List<UIComponentClassicTagBase> list = TypedCollections.dynamicallyCastList((List)
                  context.getAttributes().get(COMPONENT_TAG_STACK_ATTR), UIComponentClassicTagBase.class);
          if (list == null) {
              //noinspection CollectionWithoutInitialCapacity
              list = new ArrayList<UIComponentClassicTagBase>();
              context.getAttributes().put(COMPONENT_TAG_STACK_ATTR, list);
          }
          list.add(this);
  
      }
docs: <p>Push the specified {@link UIComponentTag} instance onto our component
  tag stack, creating a stack if necessary.</p>