ArrayList<ItemStack> itemsList = new ArrayList<ItemStack>();

    @EventHandler
    public void Sieve(BlockPlaceEvent event) {
        Set<String> items = plugin.getConfig().getConfigurationSection("Sieve").getKeys(true);

        for(String itemsName : items) {
            event.getPlayer().sendMessage(itemsName);
            if(event.getBlockPlaced().getType() == Material.getMaterial(itemsName)) {
                ConfigurationSection itemConfig = plugin.getConfig().getConfigurationSection("Sieve." + itemsName);

                event.getPlayer().sendMessage(String.valueOf(itemConfig));

                for(String item : itemConfig.getStringList(".item")) {
                    CustomStack stack = CustomStack.getInstance(item);
                    if(stack != null)
                    {
                        itemsList.add(stack.getItemStack());
                    }
                    else
                    {
                        itemsList.add(new ItemStack(Material.getMaterial(item)));
                    }
                }

                Block sieve = event.getBlockPlaced().getRelative(0, -1, 0);
                if (sieve.getType() == Material.SCAFFOLDING) {
                    Bukkit.getScheduler().runTaskLater(plugin, new Runnable() {
                        @Override
                        public void run() {
                            if (event.getBlockPlaced().getType() == Material.GRAVEL) {
                                event.getBlockPlaced().setType(Material.AIR);
                                event.getBlockPlaced().getWorld().dropItemNaturally(event.getBlockPlaced().getLocation(), itemsList.get(ThreadLocalRandom.current().nextInt(0, items.size() - 1)));
                                event.getBlockPlaced().getWorld().playSound(event.getBlockPlaced().getLocation(), Sound.ENTITY_SILVERFISH_STEP, 10, -2);
                            }
                        }
                    }, 20 * itemConfig.getInt(".time"));
                }
            }
        }
    }