Add enchantment glow to items in creative mode. Requires AttributeStorage and TinyProtocol (can be added directly to your plugin).

GlowInCreativeMode.java

package com.comphenix.example;

import java.sql.Ref;
import java.util.Collections;
import java.util.UUID;

import net.minecraft.util.io.netty.channel.Channel;

import org.bukkit.Material;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import org.bukkit.enchantments.Enchantment;
import org.bukkit.entity.Player;
import org.bukkit.event.Listener;
import org.bukkit.inventory.ItemStack;
import org.bukkit.plugin.java.JavaPlugin;

import com.comphenix.example.Reflection.FieldAccessor;
import com.comphenix.example.Reflection.MethodInvoker;

public class GlowInCreativeMode extends JavaPlugin implements Listener {
    // Generate your own at uuidgenerator.net
    private static final UUID MY_RANDOM_UUID = UUID.fromString("057d9831-1966-40e4-8e57-f82b59c95a60"); 
    private static final String MY_SECRET_VALUE = "glow";
    
    private static Class<?> PACKET_WINDOW_ITEMS = Reflection.getMinecraftClass("PacketPlayOutWindowItems");
    private static Class<?> PACKET_SET_SLOT = Reflection.getMinecraftClass("PacketPlayOutSetSlot");
    
    // net.minecraft.server.VERSION.ItemStack, not org.bukkit.inventory.ItemStack:
    private static Class<Object> NMS_ITEM_STACK = Reflection.getUntypedClass("{nms}.ItemStack");
    private static Class<Object> NMS_ITEM_STACK_ARRAY = Reflection.getUntypedClass("[L{nms}.ItemStack;");
    private static FieldAccessor<Object> setSlotStacks = Reflection.getField(PACKET_SET_SLOT, NMS_ITEM_STACK, 0);
    private static FieldAccessor<Object> windowItemStacks = Reflection.getField(PACKET_WINDOW_ITEMS, NMS_ITEM_STACK_ARRAY, 0);
    
    // Convert NMS ItemStack to Bukkit ItemStack
    private static MethodInvoker GET_CRAFT_ITEM_STACK = Reflection.getMethod("{obc}.inventory.CraftItemStack", "asCraftMirror", NMS_ITEM_STACK);
    
    private TinyProtocol tiny;
    
    @Override
    public void onEnable() {
        tiny = new TinyProtocol(this) {
            @Override
            public Object onPacketOutAsync(Player reciever, Channel channel, Object packet) {
                // This check should be as efficient as possible, as it is called for EVERY packet sent to the players
                if (PACKET_WINDOW_ITEMS.isInstance(packet)) {
                    for (Object nmsItem : (Object[])windowItemStacks.get(packet)) {
                        processItemStack(getItemStack(nmsItem));
                    }
                } else if (PACKET_SET_SLOT.isInstance(packet)) {
                    processItemStack(getItemStack(setSlotStacks.get(packet)));
                }
                return packet;
            }
        };
    }
    
    private ItemStack getItemStack(Object nmsStack) {
        return (ItemStack) GET_CRAFT_ITEM_STACK.invoke(null, nmsStack); 
    }
    
    /**
     * Invoked for every stack sent to every player.
     * @param stack - the stack.
     */
    private void processItemStack(ItemStack stack) {
        if (stack == null || stack.getType() == Material.AIR) 
            return;
        
        // Consider if you should limit this to a certain type of item
        //if (stack.getType() != Material.IRON_AXE)
        //  return;
            
        if (MY_SECRET_VALUE.equals(AttributeStorage.newTarget(stack, MY_RANDOM_UUID).getData(null))) {
            // Add a fake enchantment with NbtFactory from AttributeStorage
            NbtFactory.fromItemTag(stack).put("ench", NbtFactory.createList());
        }
    }
    
    @Override
    public void onDisable() {
        tiny.close();
    }
    
    @Override
    public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
        if (sender instanceof Player) {
            Player player = (Player) sender;
            
            ItemStack stack = new ItemStack(Material.IRON_AXE);
            
            // Make it glow!
            AttributeStorage storage = AttributeStorage.newTarget(stack, MY_RANDOM_UUID);
            storage.setData(MY_SECRET_VALUE);
            
            // Always use target!
            player.getInventory().addItem(storage.getTarget());
        }
        return true;
    }
}