Java Switch Statement
Multi-Way Decisions

Switch Statement in Java

When you're faced with multiple paths of logic based on the value of a single variable, the switch statement in Java shines as a clean, readable alternative to a long series of if-else-if blocks. It helps you route your program's behavior based on specific values—like menu choices, user input, or predefined constants.

Why Use a Switch Statement?

Imagine choosing what to eat at a food court. Based on the stall number, you want to print out the food item. You can write:

if (stall == 1) {
    System.out.println("Pizza");
} else if (stall == 2) {
    System.out.println("Burger");
} else if (stall == 3) {
    System.out.println("Sushi");
} else {
    System.out.println("Option not available");
}

Or you could write this more cleanly using switch:

switch (stall) {
    case 1:
        System.out.println("Pizza");
        break;
    case 2:
        System.out.println("Burger");
        break;
    case 3:
        System.out.println("Sushi");
        break;
    default:
        System.out.println("Option not available");
}

Pizza

Java Switch Statement Syntax

switch (expression) {
    case value1:
        // code block
        break;
    case value2:
        // code block
        break;
    ...
    default:
        // default code block
}

Key Points:

• The expression must evaluate to int, char, byte, short, enum, or from Java 7 onwards, String.
• The break statement is used to terminate a case. Without it, execution "falls through" to the next case.
• The default case is optional and executes when none of the cases match.

Basic Example with Integers

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("Invalid day");
}

Wednesday

Fall-Through Behavior

If you omit break, Java continues to execute the next statements—even if the case matched!

int choice = 2;
switch (choice) {
    case 1:
        System.out.println("First");
    case 2:
        System.out.println("Second");
    case 3:
        System.out.println("Third");
}

Second
Third

This is known as fall-through, and while sometimes useful, it can also lead to bugs if not handled carefully.

Switch with Strings (Java 7+)

String fruit = "Apple";
switch (fruit) {
    case "Apple":
        System.out.println("Red fruit");
        break;
    case "Banana":
        System.out.println("Yellow fruit");
        break;
    default:
        System.out.println("Unknown fruit");
}

Red fruit

Switch Expressions (Java 14+)

Modern Java versions allow switch expressions that return values:

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

Wednesday

Nested Switch Statements

int section = 1;
int shelf = 2;
switch (section) {
    case 1:
        switch (shelf) {
            case 1:
                System.out.println("Section 1 - Shelf 1");
                break;
            case 2:
                System.out.println("Section 1 - Shelf 2");
                break;
        }
        break;
    case 2:
        System.out.println("Section 2");
        break;
}

Section 1 - Shelf 2

Best Practices and Gotchas

• Always use break unless you're intentionally falling through.
• Use default to handle unexpected inputs.
• Be cautious with variable types—switch expressions need exact matches.
• Prefer switch for fixed values; use if-else for range checks.

Real-Life Example: Menu Selection

Scanner sc = new Scanner(System.in);
System.out.println("Enter your choice: 1. Start 2. Stop 3. Exit");
int input = sc.nextInt();

switch (input) {
    case 1 -> System.out.println("System Started...");
    case 2 -> System.out.println("System Stopped.");
    case 3 -> System.out.println("Exiting System.");
    default -> System.out.println("Invalid choice.");
}

System Started...