Q001

NO.36 Given:
import java.time.LocalDate;
import static java.time.DayOfWeek.*;
public class Main {
    public static void main(String[] args) {
        var today = LocalDate.now().with(TUESDAY).getDayOfWeek();
        switch (today) {
            case SUNDAY:
            case SATURDAY:
                System.out.println("Weekend");
                break;
            case MONDAY: FRIDAY:
                System.out.println("Working");
                break;
            default:
                System.out.println("Unknown");
        }
    }
}

What is the result?

A. WorkingUnknown
B. Unknown
C. TuesdayUnknown
D. The compilation fails.
E. Tuesday
F. Working


Answer: B

LocalDate.now() 會顯示今天的日期如下。註 : 2025-07-02 是星期三

2025-07-02

LocalDate.now().with(TUESDAY)，那個 TUESDAY 需 import static java.time.DayOfWeek.TUESDAY，然後會顯示本周星期二的日期

2025-07-01

LocalDate.now().with(TUESDAY).getDayOfWeek() 會顯示如下

TUESDAY

switch 裏的 case 並沒有 TUESDAY，所以結果為 Unknown。

「case MONDAY: FRIDAY:」 這種寫法是無效的，但並不會造成編譯失敗，是可正常執行。

Q002

NO.155 Given:

LocalDate dl=LocalDate.now();
dl.pushDays(1);
dl=dl.minusMonths(2);
LocalDate d2=d1.pushWeeks(3);
d2.minusDays(4);
d2=null;
How many LocalDate objects are created in this example?
A. 2
B. 3
C. 4
D. 5


Answer: D

LocalDate 是 immutable（不可變） 的，所以每次呼叫像 plusDays()、minusMonths() 這類方法時，都會回傳一個新的 LocalDate 物件，不會改變原來的物件。