Для ядра DonationAlertsAPI - простая либа для получения новых донатов 1.0

    @EventHandler
    public void onDonation(AsyncDonationEvent e) {
        Donation donation = e.getDonation();

        String username = donation.getUsername();

        Currency currency = donation.getCurrency();
        int amount = donation.getAmountMain();

        if (currency == Currency.RUB && amount >= 500) {
            Bukkit.getOfflinePlayer(username).setWhitelisted(true);
        }
    }

    @EventHandler
    public void onDonation(AsyncDonationEvent e) {
        Donation donation = e.getDonation();

        Currency currency = donation.getCurrency();
        int amount = donation.getAmountMain();

        if (currency == Currency.RUB && amount == 150) {
            new BukkitRunnable() {
                @Override
                public void run() {
                    for (Player player : Bukkit.getOnlinePlayers()) {
                        World world = player.getWorld();

                        world.spawnEntity(player.getLocation(), EntityType.GHAST);
                    }
                }
            }.runTask(this);
        }
    }