Why I Left Java for Kotlin

https://www.meetup.com/RVA-Software-Development-User-Group/events/270789325/

Transcript

1. Why I Left Java For Kotlin Sam Edwards - @HandstandSam
2. Sam Edwards
3. Outline •The Current State of Java & Kotlin •Live Coding - Kotlin Language Features •What Else is Possible with Kotlin •Conclusion
4. I Love Java ❤
5. My First… • Job out of college was writing Java • Google App Engine Backend • Android app was written in Java
6. Java 6? Who is Using "
7. Java 7? Who is Using # $
8. Java 8? Who is Using &$ '() #'
9. Java 9,10,11,12,13,14? Who is Using *
10. Java Releases https://en.wikipedia.org/wiki/Java_version_history 10
11. Java Releases 11 J2SE 1.4 February 2002 J2SE 5.0 September 2004 Java SE 6 December 2006 Java SE 7 July 2011 Java SE 8 (LTS) March 2014 Java SE 9 September 2017 Java SE 10 March 2018 Java SE 11 (LTS) September 2018 Java SE 12 March 2019 Java SE 13 September 2019 https://en.wikipedia.org/wiki/Java_version_history
12. Kotlin
13. Kotlin 13
14. Android Community Driven Adoption
15. Officially Supported Language (2017)
16. Preferred Language for Android (2019)
17. 17
20. Kotlin Releases • Started - 2010 • 1.0 - 2016 • 1.1 - 2017 • 1.2 - 2017 • 1.3 - 2018 • 1.4 - Almost… 2020…
21. Fast Evolution of Kotlin •Decoupled From Java Virtual Machine (JVM) •Compiler Plugin + Standard Libraries -> Java Bytecode
23. 23
24. It’s The Little Things
26. Why I Left Java for Kotlin - Live Coding https://github.com/handstandsam/why-i-left-java-for-kotlin
27. My Favorite Features •Java Interop •Extension Functions •Ability to Convert Java -> Kotlin •Null Safety •Data Classes •Immutability (val) •Named Parameters •No “new” or “;” •Higher Order Functions & Lambdas •Sealed Classes •Coroutines - Reactive Programming
28. Coroutines
29. Kotlin Coroutines Explained in one slide • A function with a suspend keyword signifies it must run in a Coroutine
 
 suspend fun doNetworkRequest() : Result {
 // Network Request Occurs
 } • suspend functions must be executed within a CoroutineContext and Once inside a coroutine, code executes sequentially
 
 CoroutineContext(Dispatchers.Default).launch{
 val result = doNetworkRequest()
 processResult(result)
 }
30. “Essentially, coroutines are light-weight threads. They are launched in a context of some CoroutineScope.”
31. “Essentially, coroutines are light-weight threads. They are launched in a context of some CoroutineScope.”
32. (Developer) Happiness
33. Developer Happiness is REAL
34. Developer Happiness •Less Boilerplate •Concise & Readable Code •Handle Nullable Values Proactively •Don’t have to throw away Java code •Enables Functional Programming •Enables Reactive Programming
35. Kotlin Adoption
36. GitHub Repositories Created in 2020 • Java: 1,034,837
 https://github.com/search?q=created%3A%3E2019-01-01+language%3AJava&type=Repositories&ref=advsearch&l=Java&l= • Kotlin: 100,798 
 https://github.com/search?q=created%3A%3E2020-01-01+language%3Akotlin&type=Repositories
37. What Else is Possible with Kotlin?
38. Kotlin Multiplatform •Android + iOS Code Sharing •JavaScript •Mac, Linux, Window
39. Multiplatform Libraries https://github.com/AAkira/Kotlin-Multiplatform-Libraries
40. Kotlin Native
41. Not All Roses
42. Not All Roses •Non-Ideal Interop For Some Java Frameworks and Libraries •Pick the right tool for the job •Not everyone knows Kotlin yet •Your team may not want to do Kotlin because it’s too “risky”
43. I Love Kotlin ❤
44. Dear Java, You taught me about NullPointerExceptions, verbose code and mutable data. I will always love you, but I’ve met a language named Kotlin, and I’m moving on. Love, -Sam
45. Why I Left Java For Kotlin Sam Edwards - @HandstandSam Thank You!
47. Kotlin to Java Bytecode
48. Kotlin Compilation to Java Bytecode Code.kt Code.class Kotlin Compiler
49. Java Decompiler (Using Fernflower) Code.class Java Decompiler Code.java
50. Magic Code.kt Code.class Kotlin Compiler Java Decompiler Code.java
51. Code.kt Code.class Kotlin Compiler Java Decompiler Code.java