Java8之CompletableFuture async的理解

验证代码如下

ExecutorService executorService = Executors.newFixedThreadPool(3);
        //executorService.submit(new RuleTestRunnable(1));
        List taskList = new ArrayList<>();
        for (int i = 0; i < 30; i++) {
            taskList.add(i);
        }
        CompletableFuture a1 = CompletableFuture.supplyAsync(() -> {
            logger.info("线程1{}{}","开始");

            try {
                TimeUnit.MILLISECONDS.sleep(100);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            logger.info("线程1{}{}","结束");
            return "1";
        },executorService);
       CompletableFuture a2 = CompletableFuture.supplyAsync(() -> {

            logger.info("线程2{}{}","开始");
            try {
                TimeUnit.MILLISECONDS.sleep(100);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            logger.info("线程2{}{}","结束");
            return "1";
        },executorService);
        CompletableFuture