Overloading Dataset.map

overloadingmap.scala

trait Encoder[T]
trait JFunction[T, U]

trait Dataset[T] {
  def map[U](f: T => U)(implicit encoder: Encoder[U])
  def map[U](f: JFunction[T, U], encoder: Encoder[U])
}

trait Testing {
  implicit val e: Encoder[Int] = ???
  val f: Dataset[String] = ???

  f.map(x => x.length())
  f.map(null, e)
}