It doesn’t matter how you define your static functions, as you have methods to make them all play better with Java. To achieve the functionality of a static method in Kotlin, use companion keyword modifier. Similar to Scala Create a companion object inside a class A way of adding static methods to a class Factory pattern: private constructor in class + factory.

A class/object must be directly referenced (such as passing an instance into another function)īy using the and annotations, you can write static Kotlin functions that can be used from Java in a nice and friendly way.On the other hand, you should use a Companion or static object if you need to fulfil the following criteria: The inclusion of the class clutters things up. I currently believe that if you are writing a purely static function, you should add the function directly to the file (not inside a Companion or static object). This is a question I am still trying to answer myself. I wish JetBrains would either add a proper static keyword or make it easier to define companion variables without a complete object.StaticFunctions. They just act that way due to their singleton nature. There is also the issue, as variables inside companion objects aren’t actually static by default as seen by the JVM. Companion objects are there, but that’s a lot of boilerplate and overhead when you just want a simple static variable like a logger. It’s one of the very few annoyances that I have with Kotlin in that it’s way too difficult to define static variables. With this I would end up with SLF4J, Logback/ Log4J and now kotlin-logging. Personally however, I see little benefits to introducing yet another logging library for these benefits (it also provides some Kotlin friendly features around lambdas and lazy logging). It also does a similar thing as described above to remove the companion class when needed.

This library makes clever use of a lambda as a way to get a handle on the enclosing class name.

Static in kotlin