Kotlin Object Singleton

snippet.kt

// object class as a singleton
object Log {
  val prop = 42
  fun debug(msg: String) { ... }
  fun info(msg: String) { ... }
  fun warn(msg: String) { ... }
  fun error(msg: String) { ... }
}

// object classes can inherit from classes and interfaces
object DirectExecutor: Executor {
  override fun execute(r: Runnable) = r.run()
}

DirectExecutor.execute( runnable { 
  Log.debug("executing...") 
})