An Introduction to Inheritance

• In subclass, specify added instance fields, added methods, and changed or overridden methods

  public class SavingsAccount extends BankAccount
  {
     public SavingsAccount(double rate)
     {
        interestRate = rate;
     }
  
     public void addInterest()
     {
        double interest = getBalance() * interestRate / 100;
        deposit(interest);
     }
  
     private double interestRate;
  }

• Encapsulation: addInterest calls getBalance rather than updating the balance field of the superclass (field is private)
• Note that addInterest calls getBalance without specifying an implicit parameter (the calls apply to the same object)