B4J Question Change media volume

Is this for Javafx Mediaplayer ?

If so it has a volume method where 0 = muted and 1 = full volume.
ie,

Thanks.....my bad though, I meant system media volume........

I have been trying different things I tried using jAWTRobot RobotSingleStrikeKeyCode(174)..should be volume down... but it errors code "Invalid KeyCode. I guess because it is a special key or modifier. Is there another way to send this keystroke??....thanks.