jep-269-benchmark.java

// excerpt from the benchmark
@Warmup(iterations = 50, time = 2, timeUnit = TimeUnit.MILLISECONDS)
@Measurement(iterations = 3, time = 2, timeUnit = TimeUnit.MILLISECONDS)
@Fork(1)
@State(Scope.Benchmark)
@OutputTimeUnit(TimeUnit.MILLISECONDS)
@BenchmarkMode({ Mode.AverageTime})
public class Collections9 {
  private static ArrayList<Cat> cats = new ArrayList<>();
  private static List<String> cats9;
  private static List<String> cats8;

  @Benchmark
  public void catsNonJava9Way(){
    addCat("George");
    addCat("John");
    addCat("Mack");
    addCat("Other");
    addCat("Lorem");

    for(Cat cat : cats) {
      cat.print();
    }

  }

  @Benchmark
  public void catsJava8Way() {
    // as seen on https://openjdk.java.net/jeps/269
    cats8 = Collections.unmodifiableList(Stream.of("George", "John", "Mack", "Other", "Lorem").collect(Collectors.toList()));
    cats8.forEach(System.out::println);
  }

  @Benchmark
  public void catsJava9Way(){
    cats9 = List.of("George", "John", "Mack", "Other", "Lorem");
    cats9.forEach(System.out::println);
  }

  public void addCat(String name) {
    cats.add(new Cat(name));
  }
}