在《JAVA併發程式設計實戰》這本書裡，看到一種以前沒有見過的寫法，就是在方法裡面定義一個類，這種寫法太少見了，而且搜尋的話也沒有什麼部落格介紹過。在此記錄一下書中給出的程式碼，是符合java的語法的

public class TimedRun2 {
    private static final ScheduledExecutorService cancelExec = newScheduledThreadPool(1);

    public static void timedRun(final Runnable r,
                                
 
long timeout, TimeUnit unit)
            throws InterruptedException {
        class RethrowableTask implements Runnable {
            private volatile Throwable t;

            public void run() {
                try {
                    r.run();
                } catch (Throwable t) {
                    
 
this.t = t;
                }
            }

            void rethrow() {
                if (t != null)
                    throw launderThrowable(t);
            }
        }

        RethrowableTask task = new RethrowableTask();
        final Thread taskThread = new Thread(task);
        taskThread.start();
        cancelExec.schedule(
 
new Runnable() {
            public void run() {
                taskThread.interrupt();
            }
        }, timeout, unit);
        taskThread.join(unit.toMillis(timeout));
        task.rethrow();
    }
}