What is the proper way of replacing a nested for loop with streams in Java 8?

Question

While learning Java 8 streams and lambas, I tried to replace the following nested for loops with streams :

List deskIds = new ArrayList<>()         


        

Answer 1

I would probably write it like this:

List<Long> deskIds = service.getAllNodesDepthFirst().stream()
                                          .flatMap(p -> p.getDesks().stream())
                                          .map(Desk::getId)
                                          .collect(toList());