The switch Statement

When one value must be compared with several fixed choices, switch is often clearer than a long if-else if chain. Java evaluates the selector once, then jumps to the matching case.

Basic structure

Each case contains a constant followed by a colon. A match runs that branch, break exits the switch, and default handles every unmatched value.

int day = 4;

switch (day) {
    case 1:
        System.out.println("Monday");
        break;
    case 2:
        System.out.println("Tuesday");
        break;
    case 3:
        System.out.println("Wednesday");
        break;
    case 4:
        System.out.println("Thursday");
        break;
    case 5:
        System.out.println("Friday");
        break;
    case 6:
    case 7:
        System.out.println("Weekend");
        break;
    default:
        System.out.println("Invalid day");
}

This example covers all seven days. Cases 6 and 7 are adjacent and intentionally share one body because they produce the same result.

break and fall-through

Without break, execution continues into the following case; this is called fall-through. Unless several labels intentionally share one body, end each independent branch with break.

Case labels must be compile-time constants compatible with the selector. Traditional switch supports byte, short, int, char, String, enums, and related wrapper types, but not double.

Execution order

1. Evaluate the switch selector.
2. Find an equal case; use default if none matches.
3. Execute statements from the matched position.
4. Exit at break or at the end of the switch.

01▶int tier = 2;02 double discount = 0.0;03 switch (tier) {04     case 1:05         discount = 0.05;06         break;07     case 2:08         discount = 0.10;09         break;10     case 3:11         discount = 0.15;12         break;13     default:14         discount = 0.0;15 }16 double payable = 200.0 * (1 - discount);17 System.out.printf("Payable: %.2f%n", payable);