[OCAJP]繼承關係

Given the following classes:

public class Employee {

    public int salary;
}

public class Manager extends Employee {

    public int budget;
}

public class Director extends Manager {

    public int stockOptions;
}

And given the follow main method:

public static void main(String[] args){
    Employee employee = new Employee();
    Manager manager = new Manager();
    Director director = new Director();
    // line n1
}

Which two options fail to compile when placed at line n1 of the main method?

A.

employee.salary = 50_000;

B.

director.salary = 80_000;

C.

employee.budget = 200_000;

D.

manager.budget = 1_000_000;

E.

manager.stockOption = 500;

F.

director.stockOptions = 1_000;

題解

選項A，Employee物件本身有salary欄位，因此不會有問題。

選項B，Director物件也是Employee，有salary欄位，因此也不會有問題。

選項C，Employee物件並沒有budget欄位，編譯會有問題。

選項D，Manager物件本身有budget欄位，因此不會有問題。

選項E，Manager物件並沒有stockOption欄位，編譯會有問題。

選項F，Director物件本身有stockOption欄位，因此不會有問題。