Should I use Java 8 Streams Api to combine two Collections?

Question

I have this situation where it seems that the Java 8 Streams API would be helpful, but I\'m not fully sure how it could be.

From two Collections with distinct element ty

Answer 1

I hope I don't have any silly typos, but basically what you can do is :

List list = as
                  .stream()
                  .flatMap(a -> bs.stream().map (b -> new Pair(a,b)))
                  .collect (Collectors.toList());

1. First you create a Stream from as.
2. For each a instance
   2.1 Create a Stream of bs
   2.2 Map each b to a pair of (a,b)
3. Flatten all the pairs to a single Stream.
4. Finally I collected them to a List, though you can choose other collections.