Switch statement (traditional and enhanced with arrows, yield)

The switch statement selects one of many code blocks to execute based on the value of an expression.

Traditional switch (fall‑through)

Uses case and break to prevent fall‑through.

int day = 3;
switch (day) {
    case 1:
        System.out.println("Monday");
        break;
    case 2:
        System.out.println("Tuesday");
        break;
    case 3:
        System.out.println("Wednesday");
        break;
    default:
        System.out.println("Other day");
}

Without break, execution continues to the next case (fall‑through).

Enhanced switch (Java 14+)

Uses -> arrows (no fall‑through) and can return a value with yield.

Arrow syntax:

switch (day) {
    case 1 -> System.out.println("Monday");
    case 2 -> System.out.println("Tuesday");
    case 3 -> System.out.println("Wednesday");
    default -> System.out.println("Other day");
}

Multiple labels:

switch (day) {
    case 1, 2, 3 -> System.out.println("Weekday");
    case 6, 7 -> System.out.println("Weekend");
    default -> System.out.println("Invalid");
}

Using yield to return a value:

String result = switch (day) {
    case 1, 2, 3, 4, 5 -> "Weekday";
    case 6, 7 -> "Weekend";
    default -> "Invalid";
};

Or with block:

int numLetters = switch (day) {
    case 1 -> {
        System.out.println("Monday");
        yield 6;   // returns 6
    }
    case 2 -> {
        System.out.println("Tuesday");
        yield 7;
    }
    default -> 0;
};