Prevent overpowered enchants

    @EventHandler
    public void onSpawnItem(InventoryCreativeEvent ev) {
        // Ignore NPCs
        if (!(ev.getWhoClicked() instanceof Player)) return;

        ItemStack item = ev.getCursor();
        ItemMeta meta = item.getItemMeta();
        if (meta == null) return;
        Map<Enchantment, Integer> enchants = meta.getEnchants();
        for (Map.Entry<Enchantment, Integer> entry : enchants.entrySet()) {
            if (entry.getValue().intValue() > 5) {
                ev.setCancelled(true);
                Player p = (Player) ev.getWhoClicked();
                p.sendMessage("Nuh-uh-uh! Dirty cheater!");
            }
        }
    }