Using Java's instanceof operator I am developing a BlackJack game using Java, and it came to a point that I am using instanceof operator to determine if it is a type of some subclass.

Here's an example:

public void checkForBlackJack(Player player) {
        Hand fHand = player.getHands().get(0);
        if (fHand.getCardScore() == 21) {
            fHand.setBlackjack(true);
        }

        if(player instanceof BlackJackPlayer){
            BlackJackPlayer bjplayer = (BlackJackPlayer) player;

            if(bjplayer.isSplit()){
                //Check the users other hand if it is already blackjacked
            }
        }
    }


Is using instanceof considered to be bad for such example?  Just as an overview, here is my class diagram:



I've decided to use instanceof to check for blackjack because The Dealer can also get blackjack.
In this case you could push the isSplit method to the Player class and implement it with return false;. Then the need to instanceof disappears. 

I wouldn't say that it is bad to use instanceof but often there are other options that are better.