숙제 물어보는거 잉어취급하는건 알지만 답답해서 물어좀 볼께여

지금 결과가
Employee information || Name: Lyu Chen, Salary: 40000.0
Employee information || Name: Roy Cho, Salary: 68000.0
Employee information || Name: Tim Park, Salary: 98000.0
나오는데

원래 제 예상에로는
Employee information || Name: Lyu Chen, Salary: 40000.0
Manager information || Name: Roy Cho, Salary: 68000.0, Department: Programmer
Executive information || Name: Tim Park, Salary: 98000.0, Department: Game Producer
이리 떠야하는데 왜그런걸까요... 아무리 바꾸고 구글에서 찾아봐도 답이 안나와여

뭐가 잘못됬는지좀 (굽신)

public class Main {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args)
    {
        Employee em = new Employee("Lyu Chen", 40000);
        Manager ma = new Manager("Roy Cho", 68000, "Programmer");
        Executive ex = new Executive ("Tim Park", 98000, "Game Producer");
       
        System.out.println(em);
        System.out.println(ma);
        System.out.println(ex);
    }

}

public class Employee
{
    private String name;
    private double salary;

    public Employee (String n, double s)
    {
       name = n;
       salary = s;
    }

    public String toString()
    {
        return "Employee information || Name: " + name + ", Salary: " + salary;
    }

}

public class Manager extends Employee
{
    private String department;

    public Manager(String n, double s, String d)
    {
        super(n, s);
        department = d;
    }

    public String toStirng()
    {
        return "Manager information || Name: " + super.toString() + ", Department: " + department;
    }
}

public class Executive extends Manager
{
    public Executive(String n, double s, String d)
    {
        super(n, s, d);
    }

    public String toSTring()
    {
        return "Executive information || " + super.toString();
    }
}