Streams: Collectors.averagingInt always returns a double, even for integers

averagingInt boxes its result as a Double regardless of the source type, since an average of whole numbers is not itself guaranteed to be whole.

Code

List<Integer> scores = List.of(80, 90, 70, 100);
Double avg = scores.stream().collect(Collectors.averagingInt(Integer::intValue));
System.out.println("Average (always Double): " + avg);
System.out.println("Type: " + avg.getClass().getSimpleName());

Output

Average (always Double): 85.0
Type: Double