How can I use streams to group elements by a remainder of division by the give divisor?

I hava an inputStream of Integers and some number as a devisor. I want to have a result like this:
sumByRemainder(3, (1,2,3,4,5)) -> (0, 3), (1, 5), (2, 7)

What’s wrong with the code below?

public Map<Integer, Integer> sumByRemainder(Integer devisor, IntStream is) {
    Map<Integer, Integer> map = is.collect(Collectors.groupingBy(s -> s % devisor, 
    return map;


Did you mean:

return is
       .collect(Collectors.groupingBy(s -> s % devisor, Collectors.summingInt(x -> x)));

Note that you should to use .boxed() to get primitive value from the IntStream, instead the value in groupingBy is considered as Object and you can’t devide Object by Integer