Fast, faster, Scala

na.scala

object Scala extends App {
  import scala.collection.mutable.ArrayBuffer
  import scala.annotation.tailrec
  val items = List("foo", 23, true)
  val before = System.currentTimeMillis()
  @tailrec def adds(n: Int, absoluteResult: ArrayBuffer[Any] = ArrayBuffer()): ArrayBuffer[Any] = {
      def foo(obj : Any) = obj match {
          case _:String => "String"
          case _:Boolean => "Boolean"
          case _:Integer => "Integer"
          case _ => throw new IllegalArgumentException()
      }

      @tailrec def add(s: List[Any]): Unit = if (s.nonEmpty) {
        absoluteResult += foo(s.head)
        add(s.tail)
      }

      if(n > 0) {
        add(items)
        adds(n - 1, absoluteResult)
      } else absoluteResult
  }

  {
    val absoluteResult = adds(1000000)
    println("Took : "+(System.currentTimeMillis() - before) + " ms, number of elements : "+absoluteResult.size)
  }
}

Thanks, hope it was helpful