Stream mapping multiple types

Question

How can I convert this code to the one that uses streams? one line, if possible:

List<Key<String, ?>> keys = Lists.newArrayList();
for (Map.Entry<String, House> entry : Houses.all().entrySet()) {
    keys.add(new Key<>(entry.getKey(), 
    HousesTypes.getFor(entry.getValue()));
}
return ImmutableList.of(houseConstructor.newInstance(5, keys));

Answer 1

Well, IMO "in one line" is not a great point to use Stream because they came at a cost, but you can do something like this:

return ImmutableList.of(
  houseConstructor.newInstance(
    5, 
    Houses.all()
      .entrySet()
      .stream()
      .map(entry -> new Key<>(entry.getKey(), HousesTypes.getFor(entry.getValue()))
      .collect(Collectors.toList())
  )
);