Hands-On Object-Oriented Programming with Kotlin

Calling the Kotlin singleton class

We can also call the Kotlin singleton class in Java. Let's create a singleton class in Kotlin by using the object keyword:

object Singleton {    fun happy() {         println("I am Happy")    }}

Furthermore, we can call the Singleton class and the happy function in Java by using the INSTANCE keyword:

public static void main(String args[]) {    Singleton.INSTANCE.happy();}

Notice that we do not need to use a Kotlin filename as a reference, but the object class name, Singleton, is sufficient. We can skip the INSTANCE keyword as well. Add the @JvmStatic annotation at the beginning of the function signature:

object Singleton {    fun happy() {        println("I am Happy")    }    @JvmStatic fun excited() {        println("I am very Excited")    }}