Kotlin is a statically typed programming language for the JVM, Android and the browser designed for the industry. This presentation is an overview of Kotlin features and advantages over Java including code samples.

1. An Introduction
to Kotlin JVM language
Andrius Klimavičius

2. Intro
• JVM language
• Android and browser support.
• Developed by JetBrains
• Open Source
• First appeared in 2011
• Still in Beta (v1.0.0-beta-3595)

3. Kotlin
google: kotlin logo

4. Modern Language for
Industry
• 100% interoperable with Java
• Concise - no boilerplate code
• Safe - convert runtime errors into compile time
• Tools support (command-line, plugins)
• Targets Java 6

5. Comparison
• Runtime error -> Compile time errors

6. Kotlin addresses Java
problems
• Null references are controlled by the type system.
• No raw types
• Arrays in Kotlin are invariant
• Kotlin has proper function types, as opposed to Java’s
SAM-conversions
• Kotlin does not have checked exceptions
• Use-site variance without wildcards (<? extends T>)

7. Kotlin vs Java
• No checked exceptions
• No primitive types that are not classes
• No static members
• No non-private fields
• No wildcard-types

8. Kotlin vs Java (2)
• Function literals + Inline
functions
• Extension functions
• Null-safety
• Smart casts
• String templates
• Properties
• First-class delegation
• Type inference
• Singletons
• Range expressions
• Operator overloading
• Companion objects

9. Features
• String templates
• Named arguments & defaults (verbose code)
• Lambda expressions
• Null-Safety (nullable, non-nullable refs)
• Functional programming methods (filter,map,…)
• Extensions (like Objective-C, C#)
• Auto generated POJOs (data class)

10. Features (2)
• Destructuring Declarations
• Generics (Java)
• Ranges
• Operator Overloading
• Optional semi-colons
• Android support
• ….

11. Hello World!

12. Variables

13. String templates

14. String templates

15. Functions

16. Named params & defaults

17. Lambda expressions

18. Null-safety

19. Basic FP methods like
filtering

20. Extensions

21. Data classes

22. Smart Casts

23. Call Java from Kotlin
println("Code in Kotlin")

24. Call Kotlin from Java

25. Reference
• https://kotlinlang.org
• https://prezi.com/5krzwy15ixea/kotlin-on-
android-mobiconf-2015/