相关疑难解决方法(0)

    ExecutorService pool=Executors.newFixedThreadPool(7);
        List<Future<Hotel>> future=new ArrayList<Future<Hotel>>();
        List<Callable<Hotel>> callList = new ArrayList<Callable<Hotel>>();

        for(int i=0;i<=diff;i++){

            String str="2013-"+(liDates.get(i).get(Calendar.MONTH)+1)+"-"+liDates.get(i).get(Calendar.DATE);

            callList.add(new HotelCheapestFare(str));

        }       
     future=pool.invokeAll(callList);
for(int i=0;i<=future.size();i++){

        System.out.println("name is:"+future.get(i).get().getName());
    }

现在我想invokeAll在进入for循环之前将pool放到所有任务中,但是当我运行这个程序for循环时,在此之前执行invokeAll并抛出此异常:

java.util.concurrent.ExecutionException: java.lang.NullPointerException at 
java.util.concurrent.FutureTask$Sync.innerGet(Unknown Source) at  
java.util.concurrent.FutureTask.get(Unknown Source) at 
com.mmt.freedom.cheapestfare.TestHotel.main(TestHotel.java:6??5)

Caused by: java.lang.NullPointerException at 
com.mmt.freedom.cheapestfare.HotelCheapestFare.getHotelCheap?estFare(HotelCheapes??tFare.java:166) 
at com.mmt.freedom.cheapestfare.HotelCheapestFare.call(HotelChe??apestFare.java:219)
at com.mmt.freedom.cheapestfare.HotelCheapestFare.call(HotelChe??apestFare.java:1) 
at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source) at java.util.concurrent.FutureTask.run(Unknown Source) 
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) atjava.util.concurrent.ThreadPoolExecutor$Worker.run(Unknow??n Source)
at java.lang.Thread.run