public class BankAccountDriver {
  public static void main(String[] args) {
    BankAccount b1 = BankAccount.getInstance();
    BankAccount b2 = BankAccount.getInstance();

    System.out.println("BankAccount1 balance: " + b1.getBalance());
    System.out.println("BankAccount2 balance: " + b2.getBalance());

    b1.deposit(3000);

    System.out.println("BankAccount1 balance after deposit: " +
                       b1.getBalance());
    System.out.println("BankAccount2 balance after deposit: " +
                       b2.getBalance());
  }
}