17.11 Collection与Map的同步控制

通过Collections来自动同步整个容器，但不适用的时候也是报错的。

public class Synchronization {
    public static void main(String[] args) {
        Collection<String> c =  Collections.synchronizedCollection( new ArrayList<String>());
        List<String> list = Collections.synchronizedList(new ArrayList<String>());
        Set<String> s = Collections.synchronizedSet( new HashSet<String>());
        Set<String> ss = Collections.synchronizedSortedSet( new TreeSet<String>());
        Map<String, String> m = Collections.synchronizedMap(new HashMap<String, String>());
        Map<String, String> sm =  Collections.synchronizedSortedMap(new TreeMap<String, String>());
    }
}

并发容器的使用

public class TestConcurrent {
    public static void main(String[] args) {
        ConcurrentHashMap concurrentHashMap = new ConcurrentHashMap();
        concurrentHashMap.put("aa","111");
        concurrentHashMap.put("bb","222");
        concurrentHashMap.put("cc","333");
        Iterator iterator = concurrentHashMap.entrySet().iterator();
        concurrentHashMap.put("dd","444");
        System.out.println(iterator.next());
        concurrentHashMap.put("ee","555");
        System.out.println(iterator.next());
        System.out.println(iterator.next());
        System.out.println(iterator.next());
        System.out.println(iterator.next());
    }
}