Implement the Employee class and CompensationModel hierarchy discussed in this exercise. In addition to the firstName, lastName, socialSecurityNumber and instance variables, class Employee should provide:
A constructor that receives three Strings and a to initialize the instance variables.
A set method that allows the client code to change an Employee's CompensationModel.
An earnings method that calls the CompensationModel's earning method and returns the result.
A toString() method that displays all the information about the Employee as illustrated in the sample output.
Your code in the subclasses should call methods in the super classes whenever possible to reduce the amount of code in the subclasses and utilize the code already developed in the super classes