线程池处理 Callable任务 执行完毕都得到返回值

public class ThreadPoolDemo01 {
    public static void main(String[] args) throws Exception{
        
        ExecutorService pool = new ThreadPoolExecutor(3,5,6,
                TimeUnit.SECONDS,new ArrayBlockingQueue<>(5),
                Executors.defaultThreadFactory(),new ThreadPoolExecutor.AbortPolicy());

        //2. 给任务线程池处理(返回未来任务对象)
        Future<String> f1 = pool.submit(new MyCall(10));
        Future<String> f2 = pool.submit(new MyCall(20));
        Future<String> f3 = pool.submit(new MyCall(30));
        Future<String> f4 = pool.submit(new MyCall(40));

        //String rs = f1.get();
        //sout rs
        System.out.println(f1.get());
        System.out.println(f2.get());
        System.out.println(f3.get());
        System.out.println(f4.get());
    }
}
class MyCall implements Callable<String>{
    private int n;

    public MyCall(int n) {
        this.n = n;
    }

    @Override
    public String call() throws Exception {
        int sum = 0;
        for (int i = 1; i <= n; i++){
            sum += i;
        }
        return Thread.currentThread().getName()+"最终结果="+sum;
    }
}
取结果的话 主线程会等待任务处理完毕