code: public BoxComment.Info reply(String message) {
          JsonObject itemJSON = new JsonObject();
          itemJSON.add("type", "comment");
          itemJSON.add("id", this.getID());
  
          JsonObject requestJSON = new JsonObject();
          requestJSON.add("item", itemJSON);
          if (BoxComment.messageContainsMention(message)) {
              requestJSON.add("tagged_message", message);
          } else {
              requestJSON.add("message", message);
          }
  
          URL url = ADD_COMMENT_URL_TEMPLATE.build(this.getAPI().getBaseURL());
          BoxJSONRequest request = new BoxJSONRequest(this.getAPI(), url, "POST");
          request.setBody(requestJSON.toString());
          BoxJSONResponse response = (BoxJSONResponse) request.send();
          JsonObject responseJSON = JsonObject.readFrom(response.getJSON());
  
          BoxComment addedComment = new BoxComment(this.getAPI(), responseJSON.get("id").asString());
          return addedComment.new Info(responseJSON);
      }
docs: Replies to this comment with another message.
  @param  message the message for the reply.
  @return info about the newly created reply comment.