code: public static JsonNode from(InstanceDescription description, Json json) {
          ObjectNode node = json.newObject();
          node.put("classname", description.getComponentDescription().getName())
                  .put("invalid", description.getState() == ComponentInstance.INVALID)
                  .put("reason", extractInvalidityReason(description));
          return node;
      }
docs: Creates the Json representation for an invalid controller.
  
  @param description the instance's description
  @param json        the json service
  @return the json representation