JavaOne 2016 - Kotlin: The Language of The Future For JVM?
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This document discusses Kotlin as a potential future language for the JVM. It provides an overview of Kotlin's features like concise and safe syntax, tooling support, interoperability with Java, and growing adoption by companies. The document outlines how Kotlin is easy to learn and use, supports multi-target platforms, and allows easy migration from Java. It also covers Kotlin concepts like null safety, extensions functions, and its REPL environment. Some minor limitations are noted but the overall message is that Kotlin is a productive and modern alternative to Java for the JVM.
![Kotlin: The Language of The
Future For JVM?
Leonardo Zanivan @ JavaOne Latin America 2016 [SES12196]](https://image.slidesharecdn.com/ses12196-kotlin-alinguagemdofuturodajvm-160629145007/85/JavaOne-2016-Kotlin-The-Language-of-The-Future-For-JVM-1-320.jpg)
JavaOne 2016 - Kotlin: The Language of The Future For JVM?
- 1. Kotlin: The Language of The Future For JVM? Leonardo Zanivan @ JavaOne Latin America 2016 [SES12196]
- 2. Who am I? ➔ Leonardo Zanivan ◆ Software Architect ◆ OSS Contributor ◆ GUJavaSC Member ◆ JCP Member
- 3. First things first ➔ Why Kotlin? ◆ Concise ◆ Safe ◆ Versatile ◆ Interoperabile ◆ Tooling
- 4. First things first ➔ History ◆ Conceived in 2010 ◆ Language and compiler are open source (Apache 2) ◆ To be a modern industry standard language ◆ With static typing and a smooth migration path
- 5. First things first ➔ Why should I care? ◆ Enterprise class support ◆ Production ready ◆ Java #1 language ◆ Productivity
- 6. First things first ➔ Who is using? ◆ GMC ◆ Expedia ◆ Prezi.com ◆ Telegram ◆ 99 Taxis ◆ JetBrains (IDEA, YouTrack, TeamCity)
- 7. Easy to learn ➔ Extensive documentation ◆ Online reference http://kotlinlang.org/docs ◆ Online editor & training http://try.kotlinlang.org ◆ Language documentation (PDF with 153 pages) ◆ Books (Kotlin in Action and Kotlin for Android) ◆ GitHub and StackOverflow activity
- 8. Easy to learn ➔ Fast startup ◆ Intuitive, easy to read & write (opposed to Scala) ◆ No force Functional or OOP styling
- 9. Easy to learn Online editor & training http://try.kotlinlang.org
- 10. Easy to use ➔ Tooling support ◆ IDEA Community & Ultimate ◆ Android Studio ◆ Eclipse ◆ Maven / Ant / Gradle ◆ NetBeans plugin (experimental) ◆ Sonar plugin (experimental)
- 11. Multi target support ➔ Java ➔ Android * ➔ JavaScript (experimental)
- 12. Easy to migrate ➔ Mix Java and Kotlin source files in the same project ➔ Java to Kotlin source conversion tool ➔ Compatible with Java 6 bytecode (100% compatible) ➔ Integrate with existing Java frameworks ➔ No runtime overhead ➔ No cost to adopt
- 13. KDoc ➔ Dokka is the documentation engine for Kotlin.
- 14. Feature: Null safety out-of-the-box val givenName: String? = null val len = givenName?.length //assign null val len = givenName!!.length //assert null
- 15. Feature: Lean syntax (no get/set) data class Book(var title: String, var author: Author) val book = Book(“Kotlin at JavaOne”,”Leonardo”) println(book.title)
- 16. Feature: Smart casts and type inference if (node is Leaf) { return node.symbol; } val myString = "Some text"
- 17. Functional programming val numbers = arrayListOf(-42, 17, 13, -9, 12) val nonNegative = numbers.filter { it >= 0 }
- 18. Easy singletons object CardFactory { fun getCard(): Card { return Card(); } }
- 19. Default arguments class NutritionFacts(val foodName: String, val calories: Int, val protein: Int = 0, val carbohydrates: Int = 0) { }
- 20. Named arguments val burger = NutritionFacts("Hamburger", calories = 541, protein = 14) val rice = NutritionFacts("Rice", calories = 312, carbohydrates = 23)
- 21. Extension functions fun Activity.toast(message: CharSequence, duration: Int = Toast.LENGTH_SHORT) { Toast.makeText(this, message, duration).show() }
- 23. Other features ➔ Exceptions are all unchecked ➔ Easy to use builder pattern (copy) ➔ Operator overloading (==, +, -, !, etc.) ➔ Better generics syntax (no wildcards) ➔ Automatic delegation pattern syntax ➔ String interpolation (idioms) ➔ KAPT (Kotlin annotation processor) ➔ What about multi-threading, etc? It’s all in Java!
- 24. Comparison w/ other emergent (flame war) ➔ Node.js ◆ No support to Java ecosystem ◆ Java is way faster than Node.js ➔ Go ◆ Statically linked (no VM) ◆ No support to Java ecosystem ◆ JVM is faster than Go
- 25. What’s the catch? ➔ Data class can’t inherit or be inherited ➔ Classes are final by default (you need to open) ➔ Compilation is incremental only in IDEA and Gradle ➔ Lack some FP functions (can use funKTionale lib) ➔ Null safety checks could be trick in the beginning ➔ Some reserved words conflicts (Mockito*)
- 26. Roadmap ➔ async/await/yield ➔ Data class hierarchy support ➔ Type aliases ➔ Bound method references ➔ Take advantage of Java 7/8 bytecode enhancements ➔ Back to work on JavaScript support
- 27. DEMO