Solved help with reflection

hey there, this will open a book for a player

non reflection code

Code:

private void openBook(ItemStack book, Player p) {
    int slot = p.getInventory().getHeldItemSlot();
    ItemStack old = p.getInventory().getItem(slot);
    p.getInventory().setItem(slot, book);
    ByteBuf buf = Unpooled.buffer(256);
    buf.setByte(0, (byte) 0);
    buf.writerIndex(1);
    PacketPlayOutCustomPayload packet = new PacketPlayOutCustomPayload("MC|BOpen", new
    PacketDataSerializer(buf));
    ((CraftPlayer) p).getHandle().playerConnection.sendPacket(packet);
    p.getInventory().setItem(slot, old);
}

the reflection code

Code:

private void book(ItemStack book, Player player) {

    int slot = player.getInventory().getHeldItemSlot();
    ItemStack old = player.getInventory().getItem(slot);
    player.getInventory().setItem(slot, book);
    ByteBuf buf = Unpooled.buffer(256);
    buf.setByte(0, (byte) 0);
    buf.writerIndex(1);
    try {
         //get minecraft server version
        String version = Bukkit.getServer().getClass().getPackage().getName().replace(".", ",").split(",")[3];
        //get player handle
        Object nmsPlayer = player.getClass().getMethod("getHandle").invoke(player);
        //get player connection
        Object connection = nmsPlayer.getClass().getField("playerConnection").get(nmsPlayer);
        //get the PacketDataSerializer
        classClass<?> packetDataSerializer = Class.forName("net.minecraft.server." + version +
        ".PacketDataSerializer");
        Constructor<?> packetDataSerializerConstructor = packetDataSerializer.getConstructor(ByteBuf.class);
        Class<?> packetPlayOutCustomPayload = Class.forName("net.minecraft.server." + version +
        ".PacketPlayOutCustomPayload");
        Constructor packetPlayOutCustomPayloadConstructor =
        packetPlayOutCustomPayload.getConstructor(String.class, Class.forName("net.minecraft.server." +
        version + ".PacketDataSerializer"));
        connection.getClass().getMethod("sendPacket", Class.forName("net.minecraft.server." + version +
        ".Packet")).invoke(connection, packetPlayOutCustomPayloadConstructor.newInstance("MC|BOpen",
        packetDataSerializerConstructor.newInstance(buf)));
    } catch (Exception ex) {
         player.getInventory().addItem(book);
    }
    player.getInventory().setItem(slot, old);
}