Grouped by commas

My:
import java.text.NumberFormat
import java.util.Locale
object Kata {

  def groupByCommas(n: Int): String =  NumberFormat.getNumberInstance(Locale.US).format(n)

}

Other:
object Kata {
  def groupByCommas(n: Int): String = java.text.NumberFormat.getInstance.format(n)
}