public static void init() {
        int customerIndex = 0;
        for (int bal=-1000; bal <= 1000; bal+=50) {
            BankAccount newAccount =
                new BankAccount(customerIds[customerIndex], BigInteger.valueOf(bal), BigInteger.valueOf(-2000));
            customerIndex = (customerIndex+1)%customerIds.length;
            christmasBank.addAccount(newAccount);
        }
    }