如何在java中链接两个列表？

List<Object> list1 = new ArrayList<>();
List<Object> list2 = new ArrayList<>();
List<Object> mergedList = new ArrayList<>();

// 将list1的所有元素添加到mergedList中
mergedList.addAll(list1);

// 将list2的所有元素添加到mergedList中
mergedList.addAll(list2);

List<Object> list1 = new ArrayList<>();
List<Object> list2 = new ArrayList<>();

list1.addAll(list2);

List<?> list1 = new ArrayList<>();
List<?> list2 = new ArrayList<>();
List<Object> mergedList = new ArrayList<>();

// 将list1的所有元素添加到mergedList中
mergedList.addAll(list1);

// 将list2的所有元素添加到mergedList中
mergedList.addAll(list2);

List<?> list1 = new ArrayList<>();
List<?> list2 = new ArrayList<>();

List<Object> mergedList = new ArrayList<>(list1);
mergedList.addAll(list2);

List<Object> list1 = new ArrayList<>();
List<Object> list2 = new ArrayList<>();
List<Object> mergedList = new ArrayList<>();

Collections.addAll(mergedList, list1.toArray());
Collections.addAll(mergedList, list2.toArray());

List<Object> list1 = new ArrayList<>();
List<Object> list2 = new ArrayList<>();
List<Object> mergedList = new ArrayList<>(list1);

Collections.addAll(mergedList, list2.toArray());

List<Object> list1 = new ArrayList<>();
List<Object> list2 = new ArrayList<>();

List<Object> mergedList = Stream.concat(list1.stream(), list2.stream())
                               .collect(Collectors.toList());

List<Object> list1 = new ArrayList<>();
List<Object> list2 = new ArrayList<>();

List<Object> mergedList = Stream.of(list1, list2)
                               .flatMap(List::stream)
                               .collect(Collectors.toList());