Life Beyond Java 8 (July 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 session we’ll 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. IntelliJ IDEA ©JetBrains. All rights reserved Life Beyond Java 8 Trisha Gee (@trisha_gee)
 Developer Advocate & Java Champion, JetBrains
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
8. We have two types of releases Releases and LTS (Long Term Support) releases
10. $$$ $$$
11. $$$ $$$
12. https://flic.kr/p/8xhk74
13. Use $free Oracle OpenJDK
14. Java 14
15. Use $free Oracle OpenJDK But upgrade every 6 months
16. Use an LTS version
17. Java 11
18. Use an LTS version But you may have to pay to use it in production
19. https://jdk.dev
21. Why bother?
22. Java 11
23. (Current LTS release)
24. JShell
25. var
26. Convenience Factory Methods for Collections
27. Collecting to Unmodifable Collections items.stream()
 .filter(Objects!::nonNull) .map(Object!::toString) .collect(Collectors.toUnmodifiableList());
28. New Methods on Stream API items.stream()
 .takeWhile(user !-> user.count() < maxCount)
 .forEach(user !-> position.incrementAndGet());

29. Predicate.not()
30. New Methods on Optional
31. Built in Http Client
32. • https://blog.jetbrains.com/idea/2017/10/creating- multi-release-jar-files-in-intellij-idea/ Multi Release Jar Files
33. Jigsaw
34. Java Module System
35. JLink
36. Java 14
37. (The latest version)
38. (for now!!...)
39. https://blog.jetbrains.com/idea/2019/02/java-12-and-intellij-idea/ Switch Expressions
40. https://blog.jetbrains.com/idea/2019/11/java-13-and-intellij-idea Text Blocks (Preview)
41. https://blog.jetbrains.com/idea/2020/03/java-14-and-intellij-idea/ Pattern Matching for instanceof (Preview)
42. https://blog.jetbrains.com/idea/2020/03/java-14-and-intellij-idea Records (Preview)
43. Java 15
44. JEP 378: Text Blocks (Standard)
45. JEP 375: Pattern Matching for instanceof (Second Preview)
46. • Non-private constructors • Annotations • Local Types JEP 384: Records (Second Preview)
47. JEP 360: Sealed Types (Preview)
48. JEP 371: Hidden Classes
49. JEP 377: ZGC: A Scalable Low-Latency Garbage Collector (Production)
50. https://openjdk.java.net/projects/jdk/15/
51. The Future
52. • Project Amber • Valhalla • Loom • More Garbage Collection improvements • Proposed New Project: Leyden And in the future?
53. The Business Doesn’t Care About Language Features
54. Performance
55. Use of Memory
56. • 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)
57. • 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)
58. Cost
59. Cost £$€
60. Tips for Migration
61. Run on updated JDK
62. Run on updated JDK It might “just work”
63. Address compiler warnings
64. Address compiler warnings …they are there for a reason
65. Update your dependencies
66. Update your dependencies And add new ones
67. Update your build tool
68. Update your build tool Updated Maven and Gradle required
69. Compile against updated JDK
70. Compile against updated JDK …and start using the shiny new features
71. https://www.infoq.com/articles/upgrading-java-8-to-12/
72. In Summary
73. Modern Java Can Help You
74. Modern Java Can Help You Performance, cost, maintenance…
75. There are two upgrade options
76. There are two upgrade options To Java 11 (LTS) or to Java 14 (upgrade every 6 months)
77. Upgrade Now And Reduce Future Pain
78. Upgrade Now And Reduce Future Pain …and keep upgrading, at least in CI
79. http://bit.ly/beyond-j8 @trisha_gee