ClassCastException when casting object Array to Long array

Question

I get this exception when i try to cast an Object array to a Long array.

Exception in thread \"main\" java.lang.ClassCastException: [Ljava.lang.O

Answer 1

change

returnValues = (Long[]) hotelRooms.keySet().toArray();

to

returnValues = hotelRooms.keySet().toArray(new Long[hotelRooms.size()]);

and let me know if it works :-)