Even Java manages to get your example to work efficiently with map/filter. It's not rocket science. Just because some library designers screwed it up doesn't invalidate the whole concept.
but java provides collect. which is, like, the right way to do it.
I'm just sort of mystified that people are defending map.filter over filter.map (which isn't crazy, as name.isValidPerson isn't provided.) but, you know, fold is a thing.
