I think you mean var, not val.

If you were using val you would do:

  class Kitty(val purrVolue: Int)

which would turn out to be in Java:

  public class Kitty {
    private final int purrVolume;
    public Kitty(final int purrVolume) {
       this.purrVolume = purrVolume;
    }
    public int getPurrVolume() { return purrVolume; }
  }