Nullability In Kotlin

This is a presentation about null safety in Kotlin. Basically, an overview of the history of the "null reference", how Kotlin has been designed to handle it. And a few cool tools Kotlin offers to handle absence of values safely.

Transcript

1. TAKE A SEAT
2. WELCOME
3. NULLABILITY IN KOTLIN Michael Bukachi, @michaelbukachi Software Engineer, Mobidev Ke
4. Nullability Null Reference ~ “Billion Dollar Mistake”
5. Nullability Null Reference: • Created in 1964 • Later introduced into JAVA (every object can be null • Billions of dollars have been spent to handle and fix errors it introduces
6. Nullability Programming Languages should be designed with safety and reliability in mind
7. Nullability A programming language designer is responsible for the mistakes of the consumers
8. Nullability A programming language designer is responsible for the mistakes of the consumers
9. Nullability public static void main(String[] args) { String string1 = ""; String string2 = null; } What’s wrong with this picture?
10. Nullability
11. Nullability val string1: String = "" val string2: String? = null There should be a difference
12. Nullability Kotlin Nullables Any?
13. Nullability Kotlin has been built with null safety in mind
14. Nullability So what’s in the toolbox: • ?. - Null-safe operator • !! - Non-null assertion • ?.let - Null safe lambdas • ?: - Elvis operator • as? - Safe casting
15. Nullability Q&A
16. References • https://medium.com/@hinchman_amanda/null-pointer-references-the-billion-dolla r-mistake-1e616534d485 • https://medium.com/@elizarov/null-is-your-friend-not-a-mistake-b63ff1751dd5 • https://medium.com/@elizarov/dealing-with-absence-of-value-307b80534903 • https://www.infoq.com/presentations/Null-References-The-Billion-Dollar-Mistake- Tony-Hoare/ • https://kotlinlang.org/docs/reference/null-safety.html
17. THAT’S IT! THANK YOU