java ArrayList的深拷贝与浅拷贝问题

List<Integer> newList = new ArrayList<>(list);

List<Integer> newList = new ArrayList<>();
newList.addAll(list);

List<Integer> newList = new ArrayList<>();
newList.addAll(list);
Collections.copy(newList, list)

List<Integer> newList = list.stream().collect(toList());

// 模拟些数据
Shard shard1 = new Shard(1,"张三","node1");
Shard shard2 = new Shard(2,"李四","node2");
Shard shard3 = new Shard(3,"王五","node3");
List<Shard> list = Arrays.asList(shard1, shard2, shard3);
// 拷贝一个新的list
List<Shard> newList = new ArrayList<>();
newList.addAll(list);
Collections.copy(newList, list);
// 修改新的list里数据
newList.forEach(e -> e.setShardNum(4));
// 遍历旧的list
list.forEach(e -> System.out.println(e.getShardNum()));

public class CloneUtil {
    @SuppressWarnings("unchecked")
    public static <T extends Serializable> T clone(T obj){
        T cloneObj = null;
        //写入字节流
        try {
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            ObjectOutputStream obs = new ObjectOutputStream(out);
            obs.writeObject(obj);
            obs.close();
            //分配内存，写入原始对象，生成新对象
            ByteArrayInputStream ios = new ByteArrayInputStream(out.toByteArray());
            ObjectInputStream ois = new ObjectInputStream(ios);
            //返回生成的新对象
            cloneObj = (T) ois.readObject();
            ois.close();
        }catch(IOException e){
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        return cloneObj;
    }
}

for(Shard shard: list) {
  Shard newShard = CloneUtil.clone(shard);
    newList.add(newShard);
}