code: public static BoxBookmark createFromId(String bookmarkId) {
          JsonObject object = new JsonObject();
          object.add(FIELD_ID, bookmarkId);
          object.add(FIELD_TYPE, TYPE);
          return new BoxBookmark(object);
      }
docs: A convenience method to create an empty bookmark with just the id and type fields set. This allows
  the ability to interact with the content sdk in a more descriptive and type safe manner
  
  @param bookmarkId the id of folder to create
  @return an empty BoxBookmark object that only contains id and type information