which one is better? 1.master of one trade or 2.jack of all.?

Does not sound like a volleyball question.

jack of all, if this pertains to volleyball, you'd be better off being a jack of all trades rather than master at just one, this way you can be used all around the court and you can be considered a more valuable player.

l feel master of one trade.but l am jack of all.

l am a setter but l can also play any back row/libero position, hit weak side, hit strong side, and l am tall enough and block well enough to hit middle. You have to be able to play anywhere. That way if your possition is taken and you are put on the team as back up you do not just sit on the bench forever.