Why Spring Loves Kotlin

on YouTube ↗45m

" summary

Stepwise migration from Spring Boot 1 Java + JavaScript to Spring Boot 2 pure Kotlin shows concrete wins: Kotlin-specific bytecode plugin compiler plugin auto-opens Spring-annotated classes, new top-level runApplication replaces boilerplate, Spring adds Kotlin extensions for generics and null-safety integrated with Reactor Mono/Flux, reactive Spring Data repositories are usable, coroutines support is experimental, config properties remain a pain, and Kotlin/JS plus dead-code elimination shrinks front-end output to 10 KB gzipped, a production-feasible result.

AI-written summary · about

" chapters (40)

1. 0:00Intro
2. 0:30Today most popular way to build web applications
3. 1:23Step 1
4. 3:14kotlin-spring compiler plugin
5. 4:07Domain model
6. 5:03Spring MVC controller written in Java
7. 5:20Spring MVC controller written in Kotlin
8. 6:02Inferred type hints in IDEA
9. 6:37Expressive test names with backticks
10. 8:03Kotlin bytecode builtin in Spring JARS
11. 8:40Kotlin support reference documentation
12. 9:14Kotlin API documentation
13. 9:40Run Spring Application with Boot 1
14. 10:20Declaring additional beans
15. 10:32Customizing Spring Application
16. 10:49Array-like Kotlin extension for Model
17. 11:48Reified type parameters Kotlin extension
18. 13:23Leveraging Kotlin nullable information
19. 14:54Null safety of Spring APIs
20. 17:50Configuration Properties
21. 20:03JUnit 5 supports non-static
22. 21:14Specification like tests with Kotlin and JUnit 5
23. 22:03Kotlin type-safe templates
24. 24:51Reactive Streams
25. 26:33WebFlux supports various async and Reactive API
26. 27:15Reactor Flux is a Publisher for 0...n elements
27. 27:42Reactor Mono is a Publisher for 0..1 element
28. 28:19Reactive APIs are functional
29. 28:45Reactor Kotlin extensions
30. 29:51Spring WebFlux with annotations
31. 30:24Spring & Kotlin Coroutines
32. 32:42Spring WebFlux with Coroutines
33. 34:11WebFlux functional API with Kotlin DSL
34. 35:10Splitting router/handlers in integration in Boot
35. 35:42Functional handlers
36. 36:43Functional bean definition DSL
37. 38:44Using bean DSL with Spring Boot
38. 39:50Original JavaScript code
39. 40:47Kotlin to Javascript
40. 43:08Compiling Kotlin to WebAssembly instead of JavaScript

" related talks

• 01h 05mWhy Spring Loves KotlinSebastien Deleuze · SpringOne Platform 2017
• 47mWhy Spring ❤ KotlinSebastien Deleuze · Devoxx Belgium 2017
• 02h 14mFrom Spring Boot 1 in Java to Spring Boot 2 in KotlinMark Heckler, Sebastien Deleuze · Devoxx Belgium 2017
• 52mSpring into Kotlin: How to Make the Magic even more MagicalMark Heckler · Riga Dev Days 2019
• 42mThe State of Kotlin Support in SpringSebastien Deleuze · KotlinConf 2019
• 33mThe State of Kotlin Support in SpringSebastien Deleuze · Jfokus 2021
• 58mSpring and Kotlin: A Winning CombinationKenneth Kousen · Developers Summit 2021
• 27mState of Kotlin Support in SpringSebastien Deleuze · Kotlin 1.4 Online Event