Streams: IntStream.boxed() turns primitives back into a Stream<Integer>

boxed() converts a primitive IntStream into a Stream<Integer>, which is required before collecting into a generic collection like List<Integer> or Set<Integer>.

Code

List<Integer> boxed = IntStream.rangeClosed(1, 5)
        .boxed()
        .toList();
System.out.println("Boxed list: " + boxed);
System.out.println("Element type: " + boxed.get(0).getClass().getSimpleName());

Output

Boxed list: [1, 2, 3, 4, 5]
Element type: Integer