Java线程安全与非线程安全解析

public class Main {   public static void main(String[] args)   {     // 进行10次测试     for(int i = 0; i < 10; i++)     {       test();     }   }   public static void test()   {     // 用来测试的List     List<Object> list = new ArrayList<Object>();     // 线程数量(1000)     int threadCount = 1000;     // 用来让主线程等待threadCount个子线程执行完毕     CountDownLatch countDownLatch = new CountDownLatch(threadCount);     // 启动threadCount个子线程     for(int i = 0; i < threadCount; i++)     {       Thread thread = new Thread(new MyThread(list, countDownLatch));       thread.start();     }     try     {       // 主线程等待所有子线程执行完成，再向下执行       countDownLatch.await();     }     catch (InterruptedException e)     {       e.printStackTrace();     }     // List的size     System.out.println(list.size());   } } class MyThread implements Runnable {   private List<Object> list;   private CountDownLatch countDownLatch;   public MyThread(List<Object> list, CountDownLatch countDownLatch)   {     this.list = list;     this.countDownLatch = countDownLatch;   }   public void run()   {     // 每个线程向List中添加100个元素     for(int i = 0; i < 100; i++)     {       list.add(new Object());     }     // 完成一个子线程     countDownLatch.countDown();   } }