DevoxxUK Lambdas Lab

Paul Sandoz paul.sandoz at
Thu Apr 4 01:21:21 PDT 2013

On Apr 3, 2013, at 10:12 AM, Richard Warburton <richard.warburton at> wrote:
> 3. Several people requested a way to transform a boxed stream into an
> unboxed stream.  Its pretty easy to go the other way around, but there
> didn’t seem to be any utility methods for making the boxed -> unboxed
> transformation.

  Stream<Integer> s = Arrays.asList(1, 2, 3, 4).stream();
  IntStream is = s.mapToInt(Integer::intValue);

Things have been moving fast so i don't know if the lambda build you used had the overloaded map methods or map/mapToInt etc.

Note that the IntStream.boxed is implemented as:

    public final Stream<Integer> boxed() {
        return mapToObj(Integer::valueOf);

Perhaps we should document how boxed is implemented and how one can convert back?


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