How to access Kotlin companion object in Java?

Question

I convert one of my Java class to Kotlin and the class as below.

class MainApplication : Application() {     companion object {         operator fun get(context: Context): MainApplication {             return context.applicationContext as MainApplication         }     } } 

It has a static function get.

I still have a Java function accessing it.

MainApplication application = MainApplication.get(mContext); 

It was good when MainApplication is in Java. But not when MainApplication in Kotlin, the above code error

Error:(27, 54) error: cannot find symbol method get(Context) 

How could I access get in my Java code above?

Answer 1

You can add @JvmStatic annotation to the method in companion object to make Kotlin generate a static method.

class MainApplication : Application() {     companion object {         @JvmStatic fun get(context: Context): MainApplication {             return context.applicationContext as MainApplication         }     } } 

you can then access it from Java like before converting to Kotlin:

MainApplication application = MainApplication.get(mContext); 

EDIT: I feel obliged to add something I learned recently: @JvmStatic doesn't actually move where the method gets generated. It duplicates it, by generating a static method for Java in addition to the method on the companion object. Personally I think this isn't great and it can have some implications depending on a use case, so something worth knowing.

Answer 2

Ops, I got it. Just use the below.

MainApplication application = MainApplication.Companion.get(mContext);