Map is not safe
package com.xizi.unsafe; import java.util.HashMap; import java.util.Map; import java.util.UUID; import java.util.concurrent.ConcurrentHashMap; //.ConcurrentModificationException public class MapTest { public static void main(String[] args) { //map 是这样用的吗? 不是,工作中不用HashMap // HashMap<String, String> map = new HashMap<>(); //默认等价于什么?new HashMap<>(16,0.75); //加载因子 初始化容量 // HashMap<String, String> map = new HashMap<>(); Map<String, String> map = new ConcurrentHashMap<>(); for (int i = 0; i < 30; i++) { new Thread(() -> { map.put(Thread.currentThread().getName(), UUID.randomUUID().toString().substring(0, 5)); System.out.println(map); }).start(); } } }
JUC Concurrent Programming Map Collection (6)
Guess you like
Origin blog.csdn.net/weixin_45480785/article/details/105358701
Recommended
Ranking