名前が this のメソッドは Auxiliary Constructor

class Random(val self: java.util.Random) extends AnyRef with Serializable {
  /** Creates a new random number generator using a single long seed. */
  def this(seed: Long) = this(new java.util.Random(seed))

  /** Creates a new random number generator using a single integer seed. */
  def this(seed: Int) = this(seed.toLong)

  /** Creates a new random number generator. */
  def this() = this(new java.util.Random())

object Main extends App {
  // 2 番目のコンストラクタを呼び出し
  val r = new scala.util.Random(2022);
  println(r.nextInt());
}