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 12 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, 10, 11 and 12
- 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

2. Upgrading Past Java 9 Sounds Scary …and I don’t want to pay for Java
3. Super happy with Java 8, thanks
12. Starting with Java 11, Oracle will provide JDK releases under the open source GNU General Public License v2, with the Classpath Exception (GPLv2+CPE), and under a commercial license for those using the Oracle JDK as part of an Oracle product or service, or who do not wish to use open source software. This… replaces the historical “BCL” license, which had a combination of free and paid commercial terms. Donald Smith, Sr. Director of Product Management (June 2018) https://blogs.oracle.com/java-platform-group/oracle-jdk-releases- for-java-11-and-later
13. That sounds frightening, and overly complicated. Talk us through it. The Lego Batman Movie
14. That sounds frightening, and overly complicated. Talk us through it. The Lego Batman Movie
15. https://flic.kr/p/8xhk74
16. From Java 11 forward, Oracle JDK builds and OpenJDK builds will be essentially identical. Donald Smith, Sr. Director of Product Management (Sept 2018) https://blogs.oracle.com/java-platform-group/oracle-jdk-releases- for-java-11-and-later
17. https://blog.joda.org/2018/09/time-to-look-beyond-oracles-jdk.html
20. https://adoptopenjdk.net
21. https://adoptopenjdk.net/support.html
23. Language features
24. JShell
25. JShell
26. JShell
27. var
28. var
29. var
30. var
31. var
32. var
33. Convenience Factory Methods for Collections
34. Convenience Factory Methods for Collections
35. Convenience Factory Methods for Collections
36. Convenience Factory Methods for Collections
37. Collecting to Unmodifable Collections items.stream() .filter(Objects::nonNull) .map(Object::toString) .collect(Collectors.toUnmodifiableList());
38. New Methods on Stream API items.stream() .takeWhile(user -> user.count() < maxCount) .forEach(user -> position.incrementAndGet());
39. Predicate.not()
40. New Methods on Optional
41. Http Client @tddmonkey
42. Multi Release Jar Files
43. Jigsaw
44. Java Module System
45. Java Module System
46. JLink
47. And in the future?
48. Java 12: Switch expressions
49. • JEP 302: Lambda Leftovers (including underscore for param) • JEP 305: Pattern Matching (Preview) • Data Classes for Java • Project Amber • Valhalla • Loom And in the future?
51. Performance
52. Memory Usage
53. • 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 Collectors
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) • Java 12: JEP 189: Shenandoah (Experimental) • Java 12: More Updates to G1 • Java 12: More Improvements to ZGC Garbage Collectors
55. Cost £$€
56. Catch the 6 month release train
57. If It Hurts, Do It More Frequently, and Bring the Pain Forward An idea from Extreme Programming (XP) Continuous Delivery – Jez Humble & Dave Farley
59. Modularity?
60. Missing classes / methods
62. Run on updated JDK It might “just work”
63. Address compiler warnings …they are there for a reason
64. Update your dependencies And add new ones
65. Update your build tool Maven and Gradle work with Java 12
66. Compile against updated JDK …and start using the shiny new features
68. Java Is Changing …fast
69. Modern Java Can Help You Performance, cost, maintenance…
70. Upgrade Now And Reduce Future Pain …and keep upgrading, at least in CI