package jdk_source; import java.util.ArrayList; import java.util.Collections; import java.util.Iterator; import java.util.List; /** * Created by jiangyunxiong on 2018/4/30. */ public class ArrayListTest { public static void main(String[] args) { List list = new ArrayList<>(); list.add(1); list.add(2); list.add(3); List synList = Collections.synchronizedList(list); synchronized (list){ Iterator iterator = synList.iterator(); while(iterator.hasNext()){ System.out.println(iterator.next()); } } } }