Java 9 High Performance

Stream API improvements

Most of the new Stream API features in Java 9 have already been demonstrated in the section that describes Stream filtering. To remind you, here are the examples we have demonstrated based on the Stream API improvements in JDK 9:

long c1 = senators.stream()        .flatMap(s -> Stream.ofNullable(s.getParty()                               == "Party1" ? s : null))        .count();System.out.println("OfNullable: Members of Party1: " + c1);long c2 = senators.stream()        .map(s -> s.getParty() == "Party2" ? Optional.of(s)                                         : Optional.empty())        .flatMap(Optional::stream)        .count();System.out.println("Optional.stream(): Members of Party2: "                                                      + c2);senators.stream().limit(5)        .takeWhile(s -> Senate.timesVotedYes(s) < 5)        .forEach(s -> System.out.println("takeWhile(<5): "  ...