Kotlin Singleton Example

To create an Singleton in Kotlin is very simple. All you need is to declare the class with the keyword object. The init block to initialize anything that you need for the Singleton class. @Synchronized for thread safe operations.

object MySingleton {
     var counter = 0
         private set

    init {
        counter = 1
    }

    @Synchronized fun addToCounter(num:Int) {
        counter = counter + num
    }

}

References:
https://kotlinlang.org/docs/reference/object-declarations.html#object-declarations
https://antonioleiva.com/objects-kotlin/
https://stackoverflow.com/questions/40398072/singleton-with-parameter-in-kotlin