Bukkit - Saving and loading inventories.

    private Map<String, ItemStack[]> playerInventories = new HashMap<String, ItemStack[]>();

    private void saveInventory(Player p) {
        PlayerInventory pInv = p.getInventory();
        Collection<ItemStack> items = new ArrayList<ItemStack>();
        items.addAll(Arrays.asList(pInv.getContents()));
        items.addAll(Arrays.asList(pInv.getArmorContents()));

        ItemStack[] inventoryItems = items.toArray(new ItemStack[] {});
        this.playerInventories.put(p.getName(), inventoryItems);
    }

    @SuppressWarnings("deprecation")
    private void resetInventory(Player p) {
        if (!this.playerInventories.containsKey(p.getName())) return;
        p.getInventory().clear();
        p.getInventory().setArmorContents(null);
        ItemStack[] inventoryItems = this.playerInventories.get(p.getName());
        ItemStack[] playerItems = new ItemStack[inventoryItems.length - 4];
        ItemStack[] playerArmour = new ItemStack[4];
        int armourI = 0;
        for (int i = 0; i < inventoryItems.length; i++) {
            if (i < inventoryItems.length - 4) {
                playerItems[i] = inventoryItems[i];
            } else {
                playerArmour[armourI] = inventoryItems[i];
                armourI++;
            }
        }
        p.getInventory().setContents(playerItems);
        p.getInventory().setArmorContents(playerArmour);
        p.updateInventory();
    }