Switch Statements

You know if-else chains. They work great for 2-3 options. But when you have many options (like which weapon Tommy picked), the code gets ugly fast. That's where switch comes in

public class Main {
    public static void main(String[] args) {
        String weapon = "shotgun";

        switch (weapon) {
            case "pistol":
                System.out.println("Basic but reliable");
                break;
            case "shotgun":
                System.out.println("Devastating up close");
                break;
            case "rocket":
                System.out.println("Total overkill");
                break;
            default:
                System.out.println("Unknown weapon");
                break;
        }
    }
}

Output

Devastating up close

The switch checks the value of weapon and jumps to the matching case. When it finds "shotgun", it runs that block, then break tells it to stop and exit the switch

break is crucial. Without it, Java "falls through" to the next case and keeps running

public class Main {
    public static void main(String[] args) {
        int stars = 3;

        switch (stars) {
            case 1:
                System.out.println("Cops notice you");
            case 2:
                System.out.println("Cops chase you");
            case 3:
                System.out.println("Helicopter shows up");
            case 4:
                System.out.println("Special forces arrive");
            case 5:
                System.out.println("Army tanks roll in");
        }
    }
}

Output

Helicopter shows up
Special forces arrive
Army tanks roll in

Whoa, we only wanted the 3-star message, but it printed 3, 4, and 5! That's because without break, Java falls through every case below the match. Sometimes this is useful on purpose, but usually it's a bug. Always add break unless you specifically want fall-through

The correct version with break

public class Main {
    public static void main(String[] args) {
        int stars = 3;

        switch (stars) {
            case 3:
                System.out.println("Helicopter shows up");
                break;
            case 4:
                System.out.println("Special forces arrive");
                break;
            case 5:
                System.out.println("Army tanks roll in");
                break;
        }
    }
}

Output

Helicopter shows up

default is like the else in an if-else chain: it handles anything that doesn't match any case

public class Main {
    public static void main(String[] args) {
        String vehicle = "boat";

        switch (vehicle) {
            case "car":
                System.out.println("Drive on roads");
                break;
            case "bike":
                System.out.println("Weave through traffic");
                break;
            default:
                System.out.println("Some other vehicle: " + vehicle);
                break;
        }
    }
}

Output

Some other vehicle: boat

switch works with int, String, char, and enum types. Sometimes we want several cases to run the same code. Then we stack them on top of each other, with no code between them

public class Main {
    public static void main(String[] args) {
        String day = "Monday";
        switch (day) {
            case "Saturday":
            case "Sunday":
                System.out.println("Weekend");
                break;
            default:
                System.out.println("Weekday");
                break;
        }
    }
}

Notice how we stacked case "Saturday": and case "Sunday": together, with no code between them: that's intentional fall-through. Both cases run the same code. This is the one time fall-through is actually handy

Switch with int is very common too

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

        switch (menuChoice) {
            case 1:
                System.out.println("Start new game");
                break;
            case 2:
                System.out.println("Load saved game");
                break;
            case 3:
                System.out.println("Settings");
                break;
            default:
                System.out.println("Invalid choice");
                break;
        }
    }
}

Output

Load saved game

Mission: Duty Roster Classifier

The station's duty roster needs a quick classifier: given a day name, print whether it is a weekday or a weekend shift.

Store the day in a String variable named day and write a switch that:

• for "Monday", "Tuesday", "Wednesday", "Thursday", "Friday" → prints Weekday
• for "Saturday" and "Sunday" → prints Weekend
• in any other case → prints Unknown day

Examples

For "Monday":

Weekday

For "Saturday":

Weekend

For "Christmas" (not a day of the week):

Unknown day