Juc645种子 RMVB 下载(Juc620)

集合类很多都是并发不安全的集合类并发不安全解决方案1:list报错集合类并发不安全解决方案2:map、set

ArrayList（始于jdk1.2）是线程不安全的，有几率会报java.util.ConcurrentModificationExceptio
解决方案?

1.Vector替换ArrayList2.Collections（集合工具类）提供的将不安全的类转换为安全的类的方法3.JUC提供的读写安全集合类：CopyOnWriteArrayList

package juc.list;

import java.util.*;
import java.util.concurrent.CopyOnWriteArrayList;


public class Test {
    public static void main(String[] args) {
//        List list = Arrays.asList("1", "2", "3");
//        list.forEach(System.out::println);//forEach里面的参数是函数式接口

        
//        List list = new ArrayList<>();
        
//        List list = new Vector<>();
        
//        List list = Collections.synchronizedList(new ArrayList<>());//将ArrayList变得安全
        
        List list = new CopyOnWriteArrayList<>();
        for (int i = 0; i < 10; i++) {
            new Thread(() -> {
                list.add(UUID.randomUUID().toString().substring(0, 8));
                System.out.println(Thread.currentThread().getName() + "==>" + list);
            }, "线程执行" + i).start();
        }
    }
}

线程执行0==>[959cbe27, f79bb4cf]
线程执行5==>[959cbe27, f79bb4cf, 3557d56c, 9f4fbab2, 16a682a1, dab5ac15, 8d4b295d, 887d8ddd]
线程执行9==>[959cbe27, f79bb4cf, 3557d56c, 9f4fbab2, 16a682a1, dab5ac15, 8d4b295d]
线程执行6==>[959cbe27, f79bb4cf, 3557d56c, 9f4fbab2, 16a682a1, dab5ac15]
线程执行7==>[959cbe27, f79bb4cf, 3557d56c]
线程执行2==>[959cbe27, f79bb4cf, 3557d56c, 9f4fbab2, 16a682a1]
线程执行4==>[959cbe27, f79bb4cf]
线程执行8==>[959cbe27, f79bb4cf, 3557d56c, 9f4fbab2, 16a682a1, dab5ac15, 8d4b295d, 887d8ddd, a8dc1b66, 8d583264]
线程执行3==>[959cbe27, f79bb4cf, 3557d56c, 9f4fbab2, 16a682a1, dab5ac15, 8d4b295d, 887d8ddd, a8dc1b66]
Exception in thread "线程执行1" java.util.ConcurrentModificationException
	at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:911)
	at java.util.ArrayList$Itr.next(ArrayList.java:861)
	at java.util.AbstractCollection.toString(AbstractCollection.java:461)
	at java.lang.String.valueOf(String.java:2994)
	at java.lang.StringBuilder.append(StringBuilder.java:131)
	at juc.list.Test.lambda$main$0(Test.java:30)
	at java.lang.Thread.run(Thread.java:748)