[2018 oracle code one] emerging languages bowl

Emerging Languages Bowl

Speaker: Trisha Gee (JetBrains) and Eugene Petrenko (JetBrains) – moderated by Raghavan “Rags” Srinivas

For more blog posts, see The Oracle Code One table of contents

Rags talked about how this is a different format than the usual “script bowl”. I’ve never been so not disappointed

Java (Trisha)

  • Inspired features from scripting languages
    • Lambdas
    • Streams – would be hard to use without lambdas because would need anonymous inner classes
    • RPEL
    • var
  • Not a functional language, but idioms that came from functional languages
  • Not in Java
    • Immutable “var” – do you use var/val, var/let, var/final var? We have “final var”, but it isn’t immutable. Just prevents re-assignment. But are getting immutable collections.
  • Future
    • data classes [records]- Kotlin has this. Preview feature in Java 12
    • multi-line strings – Groovy has this.
    • Switch statements/pattern matching. Preview feature as well
  • Preview features are a good thing because can discuss with real code

Kotlin (Eugene)

  • Statically typed
  • Now official on Android
  • Concise – minimal boilerplate
  • Safe – avoid classes of errors like null pointers
  • Interoperable – use JVM and Android libraries
  • Tool friendly – works with any Java IDE
  • Can combine Java and Kotlin in same module
  • Kotlin invented in 2000. Version 1 came out in 2005
  • Can target Java 1.6 (or higher if want)

“The only way to learn a new programming language is by writing programs in it” -Dennis Richie

IntelliJ has plugin which gives sample tasks

Kotlin demo

  • fun main() {} – function – defaults to void return type
  • fun main() : ReturnType {} – function with return type. Can use generics in types
  • “Hello ${abc}” – string interpolation
  • Triple quotes – multi line string
  • trimIndent() – extra method
  • var/val – mutable/immutable
  • var x : String – not nullable
  • var x : String? – nullable
  • if ( x is Type) – auto casts inside if statement
  • fun Class.method() = impl – add method from outside class. It can even use instance variables from inside the class.
  • sealed class – all subclasses must be defined in same file
  • when/is – pattern matching

My take: I don’t know what the session was supposed to be, but this was fine. It was 10 minutes of Trisha and Eugene introducing Kotlin for 30. I have seen the intro to Kotlin talk before though. That said, I still needed Google for what one thing did.


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