JAVA多線程并發容器

1、ArrayList線程不安全；CopyOnWriteArrayList線程安全

package concurrent;

import java.util.ArrayList;

import java.util.Iterator;

import java.util.List;

import java.util.concurrent.CopyOnWriteArrayList;

/**
 * Auth: zhouhongliang
 * Date：2019/8/1
 * CopyOnWriteArrayList 替代 ArrayList
 */
public class CopyOnWriteArrayListDemo {
    public static void main(String[] args) {
        List<Integer> list = new CopyOnWriteArrayList<>();
        //List<Integer> list = new CopyOnWriteArrayList<>();
        for (int i=0;i<1000;i++){
            list.add(i);
        }
        Iterator iterator = list.iterator();
        while(iterator.hasNext()){
            list.remove(iterator.next());
        }
        System.out.println(list);
    }
}           

• Auth: zhouhongliang

• Date：2019/8/1

  */

  public class ConcurrentHashMapDemo {

  public static void main(String[] args) throws InterruptedException {

  Map map = new HashMap();//線程不安全

  //Map map = new Hashtable();//線程安全

  //Map map = new ConcurrentHashMap();//線程安全

  ExecutorService executorService = Executors.newCachedThreadPool();

  CountDownLatch countDownLatch = new CountDownLatch(10000);

  for (int i=0;i<10000;i++){

  final Integer index = i;

  executorService.execute(()->{

  map.put(index,index);

  countDownLatch.countDown();

  });

  }

  countDownLatch.await();

  System.out.println(map.size());