How to interleave (merge) two Java 8 Streams?

Question

 Stream a = Stream.of(\"one\", \"three\", \"five\");
 Stream b = Stream.of(\"two\", \"four\", \"six\");

What do I need

Answer 1

One solution with Iterator

final Iterator iterA = a.iterator();
final Iterator iterB = b.iterator();

final Iterator iter = new Iterator() {
  private final AtomicInteger idx = new AtomicInteger();
  @Override
  public boolean hasNext() { 
    return iterA.hasNext() || iterB.hasNext();
  }
  @Override
  public String next() {
    return idx.getAndIncrement() % 2 == 0 && iterA.hasNext() ? iterA.next() : iterB.next();
  }
};

 // Create target Stream with StreamEx from: https://github.com/amaembo/streamex    
 StreamEx.of(iter).forEach(System.out::println);

 // Or Streams from Google Guava
 Streams.stream(iter).forEach(System.out::println);

Or simply by the solution in abacus-util provided by me:

 AtomicInteger idx = new AtomicInteger();
 StreamEx.merge(a, b, (s1, s2) -> idx.getAndIncrement() % 2 == 0 ? Nth.FIRST : Nth.SECOND).forEach(Fn.println());