Life Beyond Java 8

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 15 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 9-15
- 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) Java Developer Advocacy Lead, JetBrains
2. https://blog.jetbrains.com/idea/2020/09/a-picture-of-java-in-2020/ Java 8 remains the most popular version. It is used by 75% of professional developers who use Java as their primary language.
3. https://www.infoq.com/news/2020/03/new-relic-jvm-report/ https://snyk.io/wp-content/uploads/jvm_2020.pdf “The majority of JVMs (over 85%) are running on Java 8”
4. Releases, Updates, Licensing & Support
6. We have two types of releases
7. We have two types of releases Releases and LTS (Long Term Support) releases
9. $$$ $$$
10. $$$ $$$
11. https://flic.kr/p/8xhk74
12. Java 11 Long Term Support (LTS) Release; ~3 years support
13. Java 15 Current release; be prepared to upgrade in March 2021
14. https://jdk.dev
15. IntelliJ IDEA can help you
17. Why bother?
18. Java 11 Long Term Support (LTS) 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. Java 15 Current Release
32. Switch Expressions
33. Switch Expressions https://jb.gg/ij-jdk12
34. Text Blocks
35. Text Blocks https://jb.gg/ij-jdk13
36. Hidden classes
37. Hidden classes JEP 371
38. A Scalable Low-Latency Garbage Collector
39. A Scalable Low-Latency Garbage Collector JEP 377
40. Preview Features
41. Pattern Matching for instanceof
42. Pattern Matching for instanceof https://jb.gg/ij-jdk14
43. Records
44. Records https://jb.gg/ij-jdk14
45. Sealed Types
46. Sealed Types https://jb.gg/ij-jdk15
47. https://openjdk.java.net/projects/jdk/15/
48. The Future
49. • JEP 302: Lambda Leftovers (including underscore for param) • JEP 360: Sealed Types (Preview) • JEP draft: Pattern matching for switch (Preview) • Project Amber • Valhalla • Loom • Lots of Garbage Collection improvements Java 16
50. • Project Amber • Valhalla • Loom • More Garbage Collection improvements • Proposed New Project: Leyden And in the future?
51. The Business Doesn’t Care About Language Features
52. Performance
53. Use of Memory
54. • 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)
55. • Java 12: More Updates to G1 • Java 14: Deprecate the ParallelScavenge + SerialOld GC Combination • Java 15: ZGC (Production) • Java 15: Shenandoah (Production) Garbage Collection (Java 15)
56. Cost
57. Cost £$€
58. Tips for Migration
59. Run on updated JDK
60. Run on updated JDK It might “just work”
61. Address compiler warnings
62. Address compiler warnings …they are there for a reason
63. Update your dependencies
64. Update your dependencies And add new ones
65. Update your build tool
66. Update your build tool Updated Maven and Gradle required
67. Compile against updated JDK
68. Compile against updated JDK …and start using the shiny new features
69. https://bit.ly/8-to-11
70. In Summary
71. Modern Java Can Help You
72. Modern Java Can Help You Performance, cost, maintenance…
73. There are two upgrade options
74. There are two upgrade options To Java 11 (LTS) or to Java 15 (upgrade every 6 months)
75. Upgrade Now And Reduce Future Pain
76. Upgrade Now And Reduce Future Pain …and keep upgrading, at least in CI
77. https://bit.ly/love-beyond-8 @trisha_gee