To enable class
BasePlusCommissionEmployee to directly access superclass instance variables
commissionRate, we can declare those members as
protected in the superclass. As we discussed in Section G.3, a superclass’s
protected members are accessible by all subclasses of that superclass. In the new
CommissionEmployee class, we modified only lines 6–10 of Fig. G.4 to declare the instance variables with the
protected access modifier as follows:
protected String firstName;protected String lastName;protected String socialSecurityNumber;protected double ...