List.empty vs. List() vs. new List()

Question

What the difference between List.empty, List() and new List()? When should I use which?

Answer 1

From the source code of List we have:

object List extends SeqFactory[List] {
  ...
  override def empty[A]: List[A] = Nil
  override def apply[A](xs: A*): List[A] = xs.toList
  ... 
}

case object Nil extends List[Nothing] {...}

So we can see that it is exactly the same

For completeness, you can also use Nil.