Building Applications with Buttons

• Listener class adds interest and displays the new balance:

  class AddInterestListener implements ActionListener
  {
     public void actionPerformed(ActionEvent event)
     {
        double interest = account.getBalance() * INTEREST_RATE / 100;
        account.deposit(interest);
        label.setText("balance=" + account.getBalance());
     }
  }

• Add AddInterestListener as inner class so it can have access to surrounding final variables (account and label)