@Override public void onReceive(Object message) throws Exception { if (message instanceof Work) { Work work = (Work) message; // SumSingleton sum = SumSingleton.getInstance(); Collection<Integer> result = sum(work.getListHolder().getList(), work.getNumber()); /*for(int i: work.getListHolder().getList()){ result.add(sum.compute(i, work.getNumber())); }*/ getSender().tell(result, getSelf()); logger.tell(result, getSelf()); } else { unhandled(message); } }