How to transform a List into a java.util.List

implicit def toJavaList[A](i: scala.Iterable[A]): java.util.List[A] = {
    val result = new java.util.ArrayList[A]
    i.foreach(result.add)
    java.util.Collections.unmodifiableList[A](result)
  }

Or, if you don't need a immutable List:

implicit def toJavaMutableList[A](i: scala.Iterable[A]): java.util.List[A] = {
    val result = new java.util.ArrayList[A]
    i.foreach(result.add)
    result
}

Example using javaMutableList :

val names = List("1","2","3","4","5","6","7")

val jlist: java.util.List[String] = names
jlist: java.util.List[String] = [1, 2, 3, 4, 5, 6, 7]

val shuffled = java.util.Collections.shuffle(jlist)
shuffled: Unit = ()

println(jlist)
[4, 5, 3, 7, 2, 6, 1]