refillRequisitions.set(bucket, task);
ArrayList refills = (ArrayList) refillRequisitions.get(bucket); if(refills == null) { refills = new ArrayList(); refillRequisitions.set(bucket, refills); }  refills.add(task);
    public void addRefillRequisition(Task task) {        long endTime = getEndTime(task);        int bucket = convertTimeToBucket(endTime, true);        while (bucket >= refillRequisitions.size()) {            refillRequisitions.add(null);        }        refillRequisitions.set(bucket, task);    }