example_countdownlatch

public static void main(String[] args) throws InterruptedException {
        List<Object> packages=new ArrayList<>();
        CountDownLatch countDownLatch=new CountDownLatch(100);
        for (int i=0;i<100;i++){
            int finalI = i;
            new Thread(new Runnable() {
                @Override
                public void run() {
                    //do sth
                    packages.add(finalI);
                    System.out.println(finalI);
                    countDownLatch.countDown();
                }
            }).start();
        }
        countDownLatch.await();
        //包裹全部装箱了 统一派发
        packages.forEach(System.out::println);

    }