Beyond Java 8 (2020)

Wasn’t Java 8 a fantastic update to the language? Lambdas and streams were a huge change and have helped to improve Java developers’ productivity and introduce some functional ideas to the language. Then came Java 9... and although the module system is really interesting for certain types of applications, the lack of exciting language features and uncertainty around how painful it might be to migrate to Java 9 left many applications taking a wait-and-see approach, happy with Java 8.

But now Java has a new version every six months, and suddenly Java 14 is here. We’re all still on Java 8, wondering whether we should move to a later version, which one to choose, and how painful it might be to upgrade.

In this presentation we look at:

- Why upgrade from Java 8, including language features from Java 9-14
- What sorts of issues might we run into if we do choose to upgrade
- How the support and license changes that came in with Java 11 might impact us

Transcript

1. — Trisha Gee (@trisha_gee) Developer & Technical Advocate, JetBrains Beyond Java 8
2. https://www.jetbrains.com/lp/devecosystem-2020/java/ Despite the emergence of newer versions, Java 8 is still most beloved. It is used by 3/4 of Java developers. Java 11 is growing more popular. Compared to last year, its usage has increased by 10 percentage points.
3. https://www.infoq.com/news/2020/03/new-relic-jvm-report/ https://blog.newrelic.com/technology/state-of-java/ “The majority of JVMs (over 85%) are running on Java 8”
5. Releases, Updates, 
 Licensing & Support
7. We have two types of releases Releases and LTS (Long Term Support) releases
9. $$$ $$$
10. https://flic.kr/p/8xhk74
11. Use $free Oracle OpenJDK But upgrade 6 months
12. Java 14
13. Use an LTS version But you may have to pay to use it in production
14. Java 11
15. https://jdk.dev
17. Why bother?
18. Language features in Java 11 (The current Long Term Support release)
19. JShell
20. var
21. Convenience Factory Methods for Collections
22. Collecting to Unmodifable Collections items.stream()
 .filter(Objects!::nonNull) .map(Object!::toString) .collect(Collectors.toUnmodifiableList());
23. New Methods on Stream API items.stream()
 .takeWhile(user !-> user.count() < maxCount)
 .forEach(user !-> position.incrementAndGet());

24. Predicate.not()
25. New Methods on Optional
26. Built in Http Client
27. • https://blog.jetbrains.com/idea/2017/10/creating- multi-release-jar-files-in-intellij-idea/ Multi Release Jar Files
28. Jigsaw
29. Java Module System
30. JLink
31. Language features in Java 14 (The latest version of Java)
32. https://blog.jetbrains.com/idea/2019/02/java-12-and-intellij-idea/ Switch Expressions
33. https://blog.jetbrains.com/idea/2019/11/java-13-and-intellij-idea Text Blocks (Preview)
34. https://blog.jetbrains.com/idea/2020/03/java-14-and-intellij-idea Records (Preview)
35. https://blog.jetbrains.com/idea/2020/03/java-14-and-intellij-idea/ Pattern Matching for instanceof (Preview)
36. Beyond Java 14
37. • JEP 378: Text Blocks (Standard) • JEP 375: Pattern Matching for instanceof (Second Preview) • JEP 384: Records (Second Preview) • JEP 360: Sealed Types (Preview) • JEP 371: Hidden Classes • JEP 377: ZGC: A Scalable Low-Latency Garbage Collector (Production) • https://openjdk.java.net/projects/jdk/15/ Java 15
38. • Project Amber • Valhalla • Loom • More Garbage Collection improvements • Proposed New Project: Leyden And in the future?
39. The Business Doesn’t Care About Language Features
40. Performance
41. Use of Memory
42. • Java 9: JEP 248: G1 the Default GC • Java 10: JEP 307: Parallel Full GC for G1 • Java 11: JEP 318: Epsilon (Experimental) • Java 11: JEP 333: ZGC (Experimental) Garbage Collection (Java 11)
43. • Java 12: Shenandoah (Experimental) • Java 12: More Updates to G1 • Java 12: More Improvements to ZGC • Java 13: ZGC: Uncommit Unused Memory • Java 14: ZGC on macOS and Windows • Java 14: Deprecate the ParallelScavenge + SerialOld GC Combination Garbage Collection (Java 14)
44. Cost £$€
45. Tips for Migration
46. Run on updated JDK It might “just work”
47. Address compiler warnings …they are there for a reason
48. Update your dependencies And add new ones
49. Update your build tool Updated Maven and Gradle required
50. Compile against updated JDK …and start using the shiny new features
51. https://www.infoq.com/articles/upgrading-java-8-to-12/
52. In Summary
53. Java Is Changing …fast
54. Modern Java Can Help You Performance, cost, maintenance…
55. There are two upgrade options To Java 11 (LTS) or to Java 14 (upgrade every 6 months)
56. Upgrade Now And Reduce Future Pain …and keep upgrading, at least in CI
57. http://bit.ly/beyond-j8 @trisha_gee