Challenge 2: Fallthrough vs. a Switch Expression — Possible Solution
====================================================================

SwitchDemo.java:

public class SwitchDemo {
    public static void main(String[] args) {
        int month = 2;

        // Traditional switch -- deliberately missing a break
        switch (month) {
            case 1:
            case 2:
                System.out.println("Traditional (fallthrough): Early year");
                // no break here on purpose
            case 3:
                System.out.println("Traditional (fallthrough): ...and also March!");
                break;
            default:
                System.out.println("Traditional: Some other month");
        }

        // Switch expression -- no fallthrough possible
        String season = switch (month) {
            case 1, 2 -> "Early year";
            case 3 -> "March";
            default -> "Some other month";
        };
        System.out.println("Expression (no fallthrough): " + season);
    }
}

Output:

    Traditional (fallthrough): Early year
    Traditional (fallthrough): ...and also March!
    Expression (no fallthrough): Early year

Explanation:
In the traditional switch, month == 2 matches case 2, prints its
line, and -- because that case has no break -- execution falls
straight into case 3's body and prints its line too, even though
month is not 3. The switch expression rewrite has no fallthrough
mechanism at all: only the matching branch (case 1, 2) runs, producing
exactly one result, "Early year", assigned directly to season.

WHY THIS WORKS AS AN ANSWER
------------------------------
The traditional version reproduces the exact fallthrough bug the
chapter warns about -- a missing break causing an unrelated case's
body to execute -- and the expression rewrite demonstrates the
chapter's own claim that switch expressions never fall through,
producing only the single correct branch's value.