当我尝试从继承的类中测试数据时，为什么一直出现错误

Question

我有3个不同的类，其中2个继承自1个类。我为测试这些类而编写的程序给了我一些我不理解的错误。

这是第一堂课：

    public class Employee
{
  private String employeeName;
  private double weeklySalary;
  private String idNumber;
  private String dateHired;

  public Employee()
  {
      idNumber = "";
      employeeName = "";
      dateHired = "";
      weeklySalary = 0;
  }

  public Employee(String name, String employeeID, String hiringDate)
  {
      idNumber = employeeID;
      employeeName = name;
      dateHired = hiringDate;
  }

  public double getWeeklySalary()
  { return weeklySalary; }

  public String getEmployee()
  { return employeeName; }

  public String getIDNumber()
  { return idNumber; }

  public String getdateHired()
  { return dateHired; }

  public void setEmployeeName(String name)
  { employeeName = name; }

  public void setWeeklySalary(double weekPay)
  { weeklySalary = weekPay; }

  public void setEmployeeID(String employeeID)
  { idNumber = employeeID; }

  public void setDateHired(String hiringDate)
  { dateHired = hiringDate; }

  public boolean equals(Object otherObject)
  {
      if(otherObject == this)
         return true;
      if(otherObject == null)
         return false;
      if(this.getClass() != otherObject.getClass())
         return false;
      Employee otherID = (Employee)otherObject;
      return idNumber == otherID.idNumber;
  }

  public String toString()
  {
      String result =  String.format("ID Number: %7d\nEmployee: %-20s\nDate Hired: %7d\n$%,11.2f\n",
                                                idNumber, employeeName, dateHired, weeklySalary);
      return result;
  }

}

我编写的这两个类继承自Employee类：

public class HourlyEmployee extends Employee
{
  private static double hourlyPayRate;
  private static int    hoursWorkedPerWeek;


  public HourlyEmployee()
  {
      super();
      hourlyPayRate = 0;
      hoursWorkedPerWeek = 0;
  }

  public HourlyEmployee(String name, String employeeID, String hiringDate, double hourlyPay, int hrsPerWeek)
  {
      super(name, employeeID, hiringDate);
      hourlyPayRate = hourlyPay;
      hoursWorkedPerWeek = hrsPerWeek;
  }

  public static double getHourlyPayRate()
  { return hourlyPayRate; }

  public static int getHoursWorkedPerWeek()
  { return hoursWorkedPerWeek; }

  public static void setHourlyPayRate(double hourlyPay)
  { hourlyPayRate = hourlyPay; }

  public static void setHoursWorkedPerWeek(int hrsPerWeek)
  { hoursWorkedPerWeek = hrsPerWeek; }

  public static double getWeeklySalaryHE()
  {
    double weeklySalary = 0;  
      if(hoursWorkedPerWeek <= 35)
      {
          weeklySalary = hourlyPayRate * hoursWorkedPerWeek;
      }
      else if(hoursWorkedPerWeek > 35)
      {
          int overtimeHours = hoursWorkedPerWeek - 35;
          double weeklyPay = hourlyPayRate * 35;
          double overtimePay = (hourlyPayRate * 2) * overtimeHours;
          weeklySalary = weeklyPay + overtimePay;
      }
      return weeklySalary;
  }

  public String toString()
  {
      String result =  super.toString();
      String payRate = String.format("Rate of Pay: %5d\n", hourlyPayRate);
      String hoursWorked = String.format("Hours worked per week: %5d\n", hoursWorkedPerWeek);
      return result + payRate + hoursWorked;
  }

}

...

public class Manager extends Employee
{
  private static double annualSalary;


  public Manager()
  {
      super();
      annualSalary = 0;
  }

  public Manager(String name, String employeeID, String hiringDate, double annualPay)
  {
      super(name, employeeID, hiringDate);
      annualSalary = annualPay;
  }

  public static double getAnnualSalary()
  { return annualSalary; }

  public static void setAnnualSalary(double annualPay)
  { annualSalary = annualPay; }

  public static double getWeeklySalaryM()
  {
    double weeklySalary = annualSalary / 52;
    return weeklySalary;
  }

  public String toString()
  {
      String result =  super.toString();
      String Salary = String.format("Annual Salary: %7d\n", annualSalary);
      return result + Salary;
  }

}

我为测试这些课程编写的程序在这里：

public class EmployeeTest
{
  public static void main(String[] args)
  {
     Employee billsEmployee = new Employee("Bill", "112543", "2014" );
     HourlyEmployee marysHourlyEmployee = new HourlyEmployee("Mary", "154232", "2016", 11.30, 32);
     Manager joesManager = new Manager("Joe", "225231", "2015", 45000);
     HourlyEmployee brocksHourlyEmployee = new HourlyEmployee("Brock", "552721", "2014", 15.50, 40);

     billsEmployee.getWeeklySalary();
     System.out.println(billsEmployee);

     marysHourlyEmployee.getWeeklySalaryHE();
     System.out.println();
     System.out.println(marysHourlyEmployee);

     joesManager.getWeeklySalaryM();
     System.out.println();
     System.out.println(joesManager);

     brocksHourlyEmployee.getWeeklySalaryHE();
     System.out.println();
     System.out.println(brocksHourlyEmployee);

     Employee[] employees = new Employee[4];
     employees[0] = billsEmployee;
     employees[1] = marysHourlyEmployee;
     employees[2] = joesManager;
     employees[3] = brocksHourlyEmployee;
     System.out.print("\n\n\nPrint all accounts\n\n");

     for(int i = 0; i < employees.length; i++)
     {
        System.out.println(employees[i].toString());
        System.out.print("\n\n");
     }
     if(joesManager instanceof Manager)
        System.out.println("Joe is a manager.");
  }
}

当我运行测试程序时，我收到了一系列错误：

Exception in thread "main" java.util.IllegalFormatConversionException: d != java.lang.String
    at java.util.Formatter$FormatSpecifier.failConversion(Formatter.java:4302)
    at java.util.Formatter$FormatSpecifier.printInteger(Formatter.java:2793)
    at java.util.Formatter$FormatSpecifier.print(Formatter.java:2747)
    at java.util.Formatter.format(Formatter.java:2520)
    at java.util.Formatter.format(Formatter.java:2455)
    at java.lang.String.format(String.java:2940)
    at Employee.toString(Employee.java:61)
    at java.lang.String.valueOf(String.java:2994)
    at java.io.PrintStream.println(PrintStream.java:821)
    at EmployeeTest.main(EmployeeTest.java:11)

有人可以帮我弄清楚我为了让我的程序正常运行而犯了哪些错误吗？