Callable

public class CallableTest {

    public static void main(String[] args) throws ExecutionException, InterruptedException {
        MyThread thread = new MyThread();
        // 适配类
        FutureTask futureTask = new FutureTask(thread);

        new Thread(futureTask, "A").start();
        new Thread(futureTask, "B").start();

        // get方法可能会产生阻塞
        Integer s = (Integer) futureTask.get();
        System.out.println(s);
    }
}

class MyThread implements Callable<Integer> {

    @Override
    public Integer call() throws Exception {
        System.out.println("call()");
        // 耗时的操作
        return 1024;
    }
}

// 只有一个call(),因为有缓存
call()