运行下面的代码出现图中的错误是为什么？大神请指教

Question

package inheritance;
import java.util.Date;
import java.util.GregorianCalendar;
public class Employee {
private String name;
private double salary;
private Date hireday;

public Employee(String n,double s,int year,int month,int day)
{
    name=n;
    salary=s;
    GregorianCalendar calendar=new GregorianCalendar(year,month-1,day);
    hireday=calender.getTime();
}

public String getName()
{
    return name;
}
public double getSalary()
{
    return salary;
}
public Date getHireday()
{
    return hireday;
}

public void raiseSalary(double byPercent)
{
    double raise=salary*byPercent/100;
    salary+=raise;
}

}

package inheritance;
public class Manager extends Employee {
private double bonus;
public Manager(String n,double s,int year,int month,int day)
{
super(n,s,year,month,day);
bonus=0;
}
public double getSalary();
{
double baseSalary=super.getSalary();
return baseSalary+bonus;
}
public void setBonus(double b)
{
bonus=b;
}
}

package inheritance;

public class ManagerTest {
public static void main (String[] args){
Manager boss=new Manager("Born",10000,1991,7,17);
boss.setBonus(8000);

    Employee[] staff=new Employee[3];
    staff[0]=boss;
    staff[1]=new Employee("jack",6000,1990,3,6);
    staff[2]=new Employee("Marry",7000,1992,4,8);


    for(int i=0;i<staff.length;i++)
    {
        System.out.println("name="+staff[0].getName()+"salary="+staff[i].getSalary());
    }
}

}

Answer 1

staff[0]=(Employee)boss;