code: @SuppressWarnings("unchecked")
      private Map<Contextual<?>, Object> getComponentInstanceMap() {
          ConcurrentHashMap<Contextual<?>, Object> map = (ConcurrentHashMap<Contextual<?>, Object>) getCurrentRenderContext()
                  .get(COMPONENT_MAP_NAME);
  
          if (map == null) {
              map = new ConcurrentHashMap<Contextual<?>, Object>();
              getCurrentRenderContext().put(COMPONENT_MAP_NAME, map);
          }
  
          return map;
      }
docs: /*
  Helpers for manipulating the Component/Context maps.