我有一个带有递归嵌套的xml：

<root>
  <groups>
    <group>
      <group_data>...group data...</group_data>
      <object>...object data...</object>
      <object>...object data...</object>
      <groups>
        <gropup>
          <group_data>...group data...</group_data>
          <object>...object data...</object>
          <groups>
            <group>
              <group_data>...group data...</group_data>
              <object>...object data...</object>
              <object>...object data...</object>
            </group>
            <group>
              <group_data>...group data...</group_data>
              <object>...object data...</object>
            </group>
          </goups>
        </group>
      </groups>
    </group>
  </groups>
</root>

嵌套深度可以是任意的。
如何收集所有具有全链组数据的对象？
就像这样：

class Item {
    private ItemData item;
}

class Group {
    private String groupData;
    private List<Group> groups;
    private List<Item> Items;
}

class ItemData {
    private String itemName;
}

如何在Jackson中注解递归结构？