ошибка при добавлении сотрудника. чего не хватает, чтоб заработало?

        **Задание: Программа для управления зарплатами сотрудников. 

Система оплаты зависит от ранга сотрудника. Есть 4 ранга: Manager: получает на 10% больше своей месячной зарплаты Boss: получает на 50% больше своей месячной зарплаты Employee: получает на 15% меньше своей месячной зарплаты Volunteer: не получает ничего**

    package com.jobs.view;

    import com.jobs.application.JobsController;

    public class Main {

        private static JobsController controller=new JobsController();

        public static void main(String[] args) throws Exception {

            controller.createBossEmployee("Pepe Boss", "Dirección molona", "666666666", 100.0);
            controller.createEmployee("Pedro Employee", "Dirección molona 2", "665266666", 40.0);
            controller.createEmployee("Laura Employee", "Dirección molona 3", "625266666", 45.0);
            controller.createVolunteer("Juan Volunteer", "Dirección molona 4", "614266666", "good volunteer");
            controller.createManagerEmployee("Pedro Employee", "Dirección molona 2", "665226666", 80.0);

            controller.payAllEmployeers();

            String allEmployees=controller.getAllEmployees();


            System.out.println("EMPLOYEES: " + allEmployees + " \n");
        }
    }

    package com.jobs.application;

    import com.jobs.domain.Employee;
    import com.jobs.domain.Volunteer;
    import com.jobs.persistence.EmployeeRepository;

    public class JobsController {

        private EmployeeRepository repository;

        public JobsController(){}

        public void createBossEmployee(String name, String address, String phone, double salaryPerMonth) throws Exception{      
            Employee boss = new Employee(name, address, phone, salaryPerMonth, PaymentFactory.createPaymentRateBoss());
            repository.addMember(boss);
        }

        public void createEmployee(String name, String address, String phone, double salaryPerMonth) throws Exception{      
            Employee employee = new Employee(name, address, phone, salaryPerMonth, PaymentFactory.createPaymentRateEmployee());
            repository.addMember(employee);
        }

        public void createManagerEmployee(String name, String address, String phone, double salaryPerMonth) throws Exception{
            Employee managerEmployee = new Employee(name, address, phone, salaryPerMonth, PaymentFactory.createPaymentRateManagerEmployee());
            repository.addMember(managerEmployee);
        }

        public void payAllEmployeers() {    
        }

        public String getAllEmployees() {
            return null;
        }

        public void createVolunteer(String name, String address, String phone, String description) throws Exception {
            Volunteer volunteer = new Volunteer(name, address, phone, description);
            repository.addMember(volunteer);
        }
    }

package com.jobs.domain;

public abstract class AbsStaffMember {

    protected int id;
    protected String name;
    protected String address;
    protected String phone;
    protected double totalPaid=0;

    private static int COUNTER_MEMBERS = 1;

    public AbsStaffMember(String name, String address, String phone) throws Exception {
        if (name.equals(""))
            throw new Exception();
        if (address.equals(""))
            throw new Exception();
        if (phone.equals(""))
            throw new Exception();

        this.name = name;
        this.address = address;
        this.phone = phone;
        id = COUNTER_MEMBERS;
        COUNTER_MEMBERS++;
    }

    public abstract double pay();
}


package com.jobs.domain;

public class Employee extends AbsStaffMember {

    protected double salaryPerMonth;
    protected IPaymentRate paymentRate; 

    public Employee(String name, String address, String phone, double salaryPerMonth,IPaymentRate paymentRate) throws Exception {
        super(name, address, phone);        
        if(salaryPerMonth<0) throw new Exception();
        if(paymentRate==null) throw new Exception();

        this.salaryPerMonth=salaryPerMonth;
        this.paymentRate=paymentRate;
    }

    @Override
    public double pay() {
        totalPaid=paymentRate.pay(salaryPerMonth);
        return totalPaid;
    }
}


package com.jobs.domain;

public interface IPaymentRate {
    public double pay(double salaryPerMonth);
}



package com.jobs.domain;

public class Volunteer extends AbsStaffMember {

    protected double salaryPerMonth;
    protected IPaymentRate paymentRate;


    public Volunteer(String name, String address, String phone, String description) throws Exception {
        super(name, address, phone);
        if(salaryPerMonth<0) throw new Exception();
    }

    @Override
    public double pay() {
        salaryPerMonth = 0;
        return totalPaid=paymentRate.pay(salaryPerMonth);
    }
}


package com.jobs.persistence;

import java.util.ArrayList;
import java.util.List;

import com.jobs.domain.AbsStaffMember;

public class EmployeeRepository {

    private static List<AbsStaffMember> members=new ArrayList<>();

    public EmployeeRepository(){}

    public List<AbsStaffMember> getAllMembers(){
        return new ArrayList<>(members);
    }

    public void addMember(AbsStaffMember member) throws Exception{
        if(member==null) throw new Exception();
        members.add(member);
    }
}