Define a class Employee with the following attributes:

firstName $($string$),$ lastName $($string$),$ socialSecurityNumber $($string$),$ grossSales $($double$),$ commissionRate $($double$),$ and birthDate of Date class.

Assume that payroll is processed once per month. Create a ArrayList of Employees to various employee objects. In the loop, calculate the paid roll for each Employee. Add $$100\mathrm{.}00$ to the person's payroll if the current month is the month in which the Employee's birthday occurs.

Validate the social security format is valid $($ ###$-$##$-$####$,$ where # is a digit$)$ and should be unique in the array.