Code utilising the Bukkit API (bukkit.org) to listen for when a minecraft player equips Armor

ArmorCheck.java

    /*
    * This code checks if a player edits an armor slot
     */
    @EventHandler
    public void onArmorSlot(InventoryClickEvent event) {
        if (event.getSlotType() == (InventoryType.SlotType.ARMOR) && event.getInventory().getItem(event.getSlot()) != null) {
            /* Action Code Here */
        }
    }

    /*
    * This code checks if a player moves an armor item in their inventory
     */
    Material[] armorTypes = {Material.LEATHER_HELMET, Material.LEATHER_CHESTPLATE, Material.LEATHER_LEGGINGS, Material.LEATHER_BOOTS, Material.IRON_HELMET, Material.IRON_CHESTPLATE, Material.IRON_LEGGINGS, Material.IRON_BOOTS, Material.GOLD_HELMET, Material.GOLD_CHESTPLATE, Material.GOLD_LEGGINGS, Material.GOLD_BOOTS, Material.DIAMOND_HELMET, Material.DIAMOND_CHESTPLATE, Material.DIAMOND_LEGGINGS, Material.DIAMOND_BOOTS, Material.CHAINMAIL_HELMET, Material.CHAINMAIL_CHESTPLATE, Material.CHAINMAIL_LEGGINGS, Material.CHAINMAIL_BOOTS};

    @EventHandler
    public void onArmourEquip(InventoryMoveItemEvent event) {
        for (Material material : armorTypes) {
            if (material == event.getItem().getType()) {
                /* Action Code Here */
                break;
            }
        }
    }