So far we have not talked about the interoperability with Java. We have to do before returning an object (and simply return null if it is null) then The most common reason to use apply is the initialisation of an object. For example letʼs suppose we have a class Greeter which has a function hello thatīy default prints a greeting message on the standard output:Ĭlass Greeter In Kotlin when you declare a variable, a field or a function parameter, by default they cannotīe null. This problem is to use some kind of Option monad.Īs weʼll soon see Kotlin actually does not introduce any new special wrapper type - it uses regular Java It is quite interesting - especially at times like these when the most popular way of handling One of the first features a Kotlin developer learns is the languageʼs approach to handling null values. Shiny server-side system using Kotlin as its primary language and we do not regret it. Therefore at Allegro we decided to give it a chance - we built our new Its history however dates a few years backĪnd itʼs mature and stable enough to be used for developing solid reliable applications. Kotlin may seem like a new kid on the block - itʼs been officially released only in February.

Null check in kotlin