Ad-hoc queries over collections (LINQ in Java) https://github.com/aruld/java-oneliners

Item10.java

    // Print the names of albums that have at least one track rated four or higher, sorted by name.
    albums.stream()
      .filter(a -> a.tracks.stream().anyMatch(t -> (t.rating >= 4)))
      .sorted(comparing((Album album) -> album.name))
      .forEach(album -> System.out.println(album.name));

    // Merge tracks from all albums
    List<Track> allTracks = albums.stream()
      .flatMap((Album album) -> album.tracks.stream())
      .collect(toList());

    // Group album tracks by rating
    Map<Integer, List<Track>> tracksByRating = allTracks.stream()
      .collect(groupingBy(Track::getRating));