Chap 4, #15 (Review Question IZO-809) - Sybex

[Bradley Willard]

List compiles for me, and D is what I would expect, but the answer says E works as well, but Set doesn't compile for me... what am I missing?

Doesn't compile...

Map<Boolean, Set<String>> ml =
Stream.of("I", "Love", "CodeRanch")
     .collect(Collectors.partitioningBy(so -> so.length() > 3));

This compiles fine...

Map<Boolean, List<String>> ml =
Stream.of("I", "Love", "CodeRanch")
     .collect(Collectors.partitioningBy(so -> so.length() > 3));

Thanks!

[Jeanne Boyarsky]

Bradley,
Good question. If you read the review question *really* carefully, it says when specific parameters are passed to partitioning by. This does compile so E is in fact correct:

Map<Boolean, Set<String>> ml = Stream.of("I", "Love", "CodeRanch")
   .collect(Collectors.partitioningBy(so -> so.length() > 3, Collectors.toSet()));

ps - have a cow for supplying code to explain your question (rather than just saying "I don't get why E is true")