10.16 (Accounts Payable System Modification) It's possible to include the functionality of the pay-

roll application (Figs. G.16-21) in the accounts payable application without modifying Employee

subclasses SalariedEmployee, HourlyEmployee, CommissionEmployee or BasePlusCommission-

Employee. To do so, you can modify class Employee (Fig. G.16) to implement interface Payable and

declare method getPaymentAmount to invoke method earnings. Method getPaymentAmount would

then be inherited by the subclasses in the Employee hierarchy. When getPaymentAmount is called for

a particular subclass object, it polymorphically invokes the appropriate earnings method for that

subclass. Reimplement Exercise 10.15 using the original Employee hierarchy from the payroll appli-

cation of Figs. G.16-G21 . Modify class Employee as described in this exercise, and do not modify any

of class Employee's subclasses