code: public <T extends AbstractJaxb> boolean remove(T target) {
          String id = target.getId();
          if (id == null) {
              for (int i = 0; i < 256; i++) {
                  id = UUID.randomUUID().toString();
                  if (this.getById(id) == null) {
                      target.setId(id);
                      break;
                  }
              }
          }
          return RemoveByIdUtil.removeById(id, this);
      }
docs: <p>
  delete element that has specified attribute within descendant element
  of oneself. you can't delete oneself.
  </p>
  
  @param target
  @return if success to delete, return true. if no hit, return false.