SavingsAccount.java

public class SavingsAccount extends BankAccount{

  private double interestRate;

  public SavingsAccount(double balance, double interestRate){
    super(balance);
    this.interestRate = interestRate;
  }

  public void addInterest( ){
    double interest = getBalance( ) * interestRate / 100;
    deposit(interest);
  }

}