Yourself since I’ve simplified it drastacially at the code sample above. Swift is open source so you can take a look at Which is extremely similar to a Kotlin sealed class Optional

In other words, ? and nil are just syntax sugar literals for Pretty cool, right? The Swift compiler makes all nullable values Optional under the hood. Public static Observable just ( T item ) Let’s take a look at a very short Kotlin + RxJava sample. Otherwise the type system assumes them be to be non-nullable by default.įinally! We can use the JVM and forget about the NullPointerException! When Kotlin objects have to be declared nullable explicitly, Reasonable and pragmatic design decisions - what else to wish for?Īnd, more importantly, it brought the concept of Null SafetyĪll Java objects are essentially implicitly can be null, Well, the JVM probably can be avoided by using Kotlin Native,īut at least on Android you are stuck with the JVM as an intermediate bytecode provider.īacked by a team at JetBrains behind the best IDE platform available, The drug of choice of mine at this point in time is Kotlin,īut you cannot forget about Java when using Kotlin. So let’s ask the “How” question instead of the “Why” one.

We live in the world where we just have to deal with null this way or another. However, it does not really matter if the concept of null references a good idea or a really bad one. Null References: The Billion Dollar Mistake talk. I think almost everybody in the CS world knows about the The language doesn’t “need” to do it, it would just make the code a lot more concise.Kotlin: The Problem with null January 10, 2018 I’m just trying to highlight the use of such a feature. The mechanism for this could be replacing null with Unit for example. (My specific case was to do with processing an optional parameter when handling a HTTP request)Ĭonsider this as an example: fun foo(x: Long = 1) I recently encountered a scenario where I wanted to be able to provide a nullable type argument to a function where the corresponding parameter was non-nullable with a default value.

Kotlin optional to nullable