Java™ How To Program (Early Objects), Tenth Edition

9.4.4 CommissionEmployee–BasePlusCommissionEmployee Inheritance Hierarchy Using protected Instance Variables

To enable class BasePlusCommissionEmployee to directly access superclass instance variables firstName, lastName, socialSecurityNumber, grossSales and commissionRate, we can declare those members as protected in the superclass. As we discussed in Section 9.3, 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. 9.4 to declare the instance variables with the protected access modifier as follows:

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protected final String firstName;protected final String lastName;protected final String socialSecurityNumber; ...