// 创建线程安全的List
List<Object> list = Collections.synchronizedList(new ArrayList<>());

// 创建线程安全的Map
Map<String, Object> map = Collections.synchronizedMap(new HashMap<String, Object>());

比较实用！！

创建线程安全的集合还可以使用以下的方法：

//map
Map<String, Object> map = new ConcurrentHashMap<String, Object>();
ConcurrentSkipListMap<String, Object> skipListMap = new ConcurrentSkipListMap<>();

//list
List<?> list = new Vector<>();
CopyOnWriteArrayList copyOnWriteArrayList = new CopyOnWriteArrayList();
CopyOnWriteArraySet copyOnWriteArraySet = new CopyOnWriteArraySet();