code: @RequestMapping(value = "/api/todolist/{index}",
              method = RequestMethod.GET, produces = {MediaType.APPLICATION_JSON_VALUE})
      public ResponseEntity<?> getTodoItem(@PathVariable("index") int index) {
          if (index > todoList.size() - 1) {
              return new ResponseEntity<>(new TodoItem(-1, "index out of range", null), HttpStatus.NOT_FOUND);
          }
          return new ResponseEntity<>(todoList.get(index), HttpStatus.OK);
      }
docs: HTTP GET