To the Moon and Beyond With Java 17 APIs!

Since moving to a 6 monthly release cadence, the Java platform is evolving more dynamically than ever before. It can be quite a challenge to stay on top of all the changes and new features.

In this talk we're going to explore the most important developments in the Java API: which classes have been added, what has been removed? Join Duke, the Java mascot for a trip to space and learn which exciting new APIs provided by the Java platform can help him with his journey:

- The Java Vector API for utilizing the SIMD capabilities of modern CPU architectures
- The Foreign Linker API for integrating with native code
- The JFR Event Streaming API for publishing JDK Flight Recorder Events

We'll also take a look at some useful changes to the Java runtime, such as CDS archives for a faster spaceship..., uhm, application launch.

Transcript

1. To the Moon and Beyond
   With Java 17 APIs!
   Gunnar Morling
   Software Engineer, Red Hat
   @gunnarmorling
   

   View Slide

2. View Slide

3. View Slide

4. #Java17APIs @gunnarmorling
   “Commit [ourselves] to
   achieving the goal, before
   this decade talk is out, of
   landing a man Duke on the
   Moon and returning him
   safely to the Earth”
   Today’s Mission
   John F. Kennedy
   

   View Slide

5. The Vector API 1
   JFR Event Streaming
   2
   3
   The Foreign Linker API
   

   View Slide

6. #Java17APIs @gunnarmorling
   ● Projects
   ○ Debezium
   ○ Quarkus
   ○ Hibernate
   ● MapStruct, JfrUnit, kcctl
   ● Java Champion
   ● @gunnarmorling
   Gunnar Morling
   Open Source Software Engineer at Red Hat
   

   View Slide

7. The Vector API
   1
   

   View Slide

8. #Java17APIs @gunnarmorling
   The Vector API
   JEPs 338 / 414 / 417
   java.util.Vector?!
   

   View Slide

9. #Java17APIs @gunnarmorling
   “Introduce an API to express vector
   computations that reliably compile at runtime
   to optimal vector instructions on supported
   CPU architectures, thus achieving
   performance superior to equivalent scalar
   computations.”
   The Vector API
   JEPs 338 / 414 / 417
   JEP 417
   

   View Slide

10. #Java17APIs @gunnarmorling
    The Vector API
    Goals
    Clear and concise API
    1
    Reliable runtime compilation
    and performance on
    x64 (SSE, AVX) and
    AArch64 (NEON, SVE)
    2
    3 4
    Platform agnostic
    Graceful degradation
    

    View Slide

11. #Java17APIs @gunnarmorling
    The Vector API
    Use Cases
    ● Image, text, signal
    processing
    ● Encryption
    ● Machine Learning
    ● etc.
    

    View Slide

12. #Java17APIs @gunnarmorling
    The Vector API
    Terminology
    

    View Slide

13. #Java17APIs @gunnarmorling
    The Vector API
    Example – Scalar
    c = -(a2 + b2)
    

    View Slide

14. #Java17APIs @gunnarmorling
    The Vector API
    Example – Vector
    

    View Slide

15. #Java17APIs @gunnarmorling
    The Vector API
    Example – Vector
    

    View Slide

16. #Java17APIs @gunnarmorling
    The Vector API
    Example – Vector
    

    View Slide

17. #Java17APIs @gunnarmorling
    The Vector API
    Example – Vector
    

    View Slide

18. #Java17APIs @gunnarmorling
    The Vector API
    Example – Vector
    

    View Slide

19. #Java17APIs @gunnarmorling
    The Vector API
    A Very Rich API
    

    View Slide

20. #Java17APIs @gunnarmorling
    The Vector API
    Example – FizzBuzz
    

    View Slide

21. #Java17APIs @gunnarmorling
    The Vector API
    FizzBuzz – Performance
    Benchmark Mode Cnt Score Error Units
    scalarFizzBuzz thrpt 5 2204774,792 ± 76581,374 ops/s
    simdFizzBuzz thrpt 5 8830433,250 ± 69955,161 ops/s
    MacBook Pro 2019 (2,6 GHz 6-Core Intel Core i7, 32GB RAM)
    

    View Slide

22. #Java17APIs @gunnarmorling
    The Vector API
    Examining Assembly Code with Hsdis
    

    View Slide

23. #Java17APIs @gunnarmorling
    The Vector API
    Examining Native Assembly
    "conditionally copies
    byte elements from
    the source operand to
    the destination
    operand depending on
    mask bits defined in
    the implicit third
    register argument"
    felixcloutier.com
    

    View Slide

24. Detour
    Identifying JDK API
    Changes by Yourself
    

    View Slide

25. #Java17APIs @gunnarmorling
    Detour: Identifying API Changes
    javaalmanac.io
    

    View Slide

26. #Java17APIs @gunnarmorling
    Detour: Identifying API Changes
    github.com/AdoptOpenJDK/jdk-api-diff
    

    View Slide

27. #Java17APIs @gunnarmorling
    Detour: Identifying API Changes
    chriswhocodes.com/jepsearch.html
    

    View Slide

28. #Java17APIs @gunnarmorling
    Detour: Identifying API Changes
    JavaDoc ab Version 17
    

    View Slide

29. 1
    JFR Event Streaming 3
    2
    The Vector API
    The Foreign Linker API
    

    View Slide

30. #Java17APIs @gunnarmorling
    ● Accessing native Memory (JEP 383)
    ● Accessing native APIs (JEP 389)
    ○ Moving specific parts to native code
    ○ Using existing native libraries
    ● Vector API
    Projekt Panama
    Integration of JVM and Native Code
    

    View Slide

31. #Java17APIs @gunnarmorling
    Foreign Linker API
    Using Method Handle
    

    View Slide

32. #Java17APIs @gunnarmorling
    Foreign Linker API
    Using Method Handle
    

    View Slide

33. #Java17APIs @gunnarmorling
    Foreign Linker API
    Using Method Handle
    

    View Slide

34. #Java17APIs @gunnarmorling
    ● Provide or create header file
    ● Generate binding (Panama EA build required)
    Foreign Linker API
    jextract
    

    View Slide

35. #Java17APIs @gunnarmorling
    Foreign Linker API
    jextract
    

    View Slide

36. #Java17APIs @gunnarmorling
    Foreign Linker API
    github.com/sundararajana/panama-jextract-samples
    

    View Slide

37. Detour
    Removed APIs
    

    View Slide

38. #Java17APIs @gunnarmorling
    ● RMI Activation
    ● Pack 200
    ● Nashorn JavaScript-Engine
    ● Deprecated for Removal in Java 17
    ○ Applet API
    ○ Security Manager
    Detour: Removed APIs
    Tackling the Maintenance Burden
    → 🤷
    → 🤷
    → Standalone Nashorn
    (ab Java 15), GraalJS
    

    View Slide

39. 1
    JFR Event Streaming
    2
    3
    The Vector API
    The Foreign Linker API
    

    View Slide

40. #Java17APIs @gunnarmorling
    OpenJDK Flight Recorder
    ● “JVM framework for troubleshooting,
    monitoring and profiling”
    ● 150+ built-in event types
    ● Support for custom events
    ● Open source since Java 11
    ● Meant for “Always on” usage in production
    

    View Slide

41. #Java17APIs @gunnarmorling
    JFR Event Types
    https://bestsolution-at.github.io/jfr-doc/
    

    View Slide

42. #Java17APIs @gunnarmorling
    JFR Event Streaming
    JEP 349
    ● Processing JFR events in “real-time”
    ● Use Cases
    ○ Export to monitoring services
    ○ Performance tests (JfrUnit)
    ○ Predictive analytics
    

    View Slide

43. #Java17APIs @gunnarmorling
    JFR Event Streaming
    API
    

    View Slide

44. #Java17APIs @gunnarmorling
    JFR Event Streaming
    Out-of-process: github.com/flight-recorder/health-report
    

    View Slide

45. #Java17APIs @gunnarmorling
    ● Performance tests based on metrics like latency/throughput
    often unstable
    ● JfrUnit
    ○ Assertions based on proxy metrics
    ○ Plain JUnit-Tests
    ○ Analysis via JDK Mission Control
    JFR Event Streaming
    Use Case: Performance Regression Tests with JfrUnit
    “Unit testing,
    for performance”
    

    View Slide

46. #Java17APIs @gunnarmorling
    JFR Event Streaming
    Asserting Socket IO with JfrUnit
    

    View Slide

47. #Java17APIs @gunnarmorling
    JFR Event Streaming
    Asserting Socket IO with JfrUnit
    

    View Slide

48. #Java17APIs @gunnarmorling
    JFR Event Streaming
    Asserting Socket IO with JfrUnit
    

    View Slide

49. #Java17APIs @gunnarmorling
    JFR Event Streaming
    Asserting Socket IO with JfrUnit
    

    View Slide

50. #Java17APIs @gunnarmorling
    JFR Event Streaming
    Asserting Socket IO with JfrUnit
    

    View Slide

51. #Java17APIs @gunnarmorling
    JFR Event Streaming
    Asserting Socket IO with JfrUnit
    

    View Slide

52. Detour
    AppCDS
    

    View Slide

53. #Java17APIs @gunnarmorling
    ● Class Data Sharing: Memory mapped class metadata
    ● Default CDS archive for JDK classes since Java 12 (JEP 341)
    ● AppCDS: CDS archive for your own classes
    Detour: Faster Start-up with AppCDS
    No Need to Go Native?
    

    View Slide

54. #Java17APIs @gunnarmorling
    Detour: AppCDS
    Quarkus App – Time to First Response
    Hetzner Cloud CX4 (4 vCPUs, 16GB RAM)
    

    View Slide

55. #Java17APIs @gunnarmorling
    Detour: AppCDS
    Start-up Time of Apache Kafka
    

    View Slide

56. View Slide

57. #Java17APIs @gunnarmorling
    Java 17 – An Update Well Worth It!
    Many Improvements Across the Board...
    Language
    API
    Runtime
    

    View Slide

58. #Java17APIs @gunnarmorling
    ● Shenandoah GC
    ● JFR support for native GraalVM binaries
    ● AArch64/Linux port
    ● Project Lilliput
    Red Hat & OpenJDK
    Multiple Contributions
    

    View Slide

59. #Java17APIs @gunnarmorling
    ● JEP Search
    https://chriswhocodes.com/jepsearch.html
    ● Blog (Vector API, JFR Event Streaming,
    AppCDS, etc.)
    https://www.morling.dev/
    ● JfrUnit
    https://github.com/moditect/jfrunit
    Resources
    

    View Slide

60. #Java17APIs @gunnarmorling
    Q&A
    gunnar@hibernate.org
    @gunnarmorling
    📧
    Contact
    

    View Slide

61. View Slide