(Java SE 8 Interfaces) Why is it useful to be able to add static methods to interfaces? (Payroll SystemModification) Modify the payroll system of Figs. 10.4–10.9 to include private instance variable...

(Payroll SystemModification)

Modify the payroll system of Figs. 10.4–10.9 to include private

instance variable birthDate in class Employee. Use class Date of Fig. 8.7 to represent an employee’s birthday. Add
get
methods to class Date. Assume that payroll is processed once permonth. Create an array of Employee variables to store references to the various employee objects. In a loop, calculate the payroll for each Employee (polymorphically), and add a $100.00 bonus to the person’s payroll amount if the current month is the one in which the Employee’s birthday occurs.