#vulnerable code 
                                public static void remove(Player player) {
        if (has(player)) {
            sendPacket(player, bars.get(player).getDestroyPacket());
            bars.remove(player);
        }
    } 
                            #location 3 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                public static void remove(Player player) {
        if (has(player)) {
            sendPacket(player, DRAGONBAR_CACHE.get(player).getDestroyPacket());
            DRAGONBAR_CACHE.remove(player);
        }
    }