switch-case in Java

What is switch-case

A switch-case compares one value against several fixed options and runs the matching one. When you would otherwise write a long else if ladder checking the same variable, a switch is cleaner and easier to read.

A basic switch

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");
}

The switch checks day against each case. It matches case 3, prints Wednesday, and break stops it there.

Why break matters

int n = 1;
switch (n) {
    case 1: System.out.println("One");
    case 2: System.out.println("Two");   // no break above!
    default: System.out.println("Done");
}

Without break, Java "falls through" and runs the following cases too. That is why each case usually ends with break — to stop after the match.

The default case

char grade = 'X';
switch (grade) {
    case 'A': System.out.println("Excellent"); break;
    case 'B': System.out.println("Good"); break;
    default:  System.out.println("Invalid grade");
}

default runs when nothing else matches — like the final else. It is good practice to always include it to handle unexpected values.

Fall-through on purpose

int month = 4;
switch (month) {
    case 3: case 4: case 5:
        System.out.println("Spring"); break;
    case 6: case 7: case 8:
        System.out.println("Summer"); break;
}

Sometimes fall-through is useful: stacking cases with no code between them lets several values share one action. Here months 3, 4 and 5 all print "Spring".

The modern switch

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

Newer Java offers an arrow form with no fall-through and no break. It can even return a value directly, making the code shorter and safer.

Common mistakes

• Forgetting break. In the classic switch, missing break causes fall-through.
• No default case. Always handle unmatched values with default.
• Using ranges. A case must be one exact value — case > 5 is invalid; use if-else for ranges.
• Wrong type. Cases must match the switch variable's type (int, char, String, enum).

Summary

• switch-case compares one value to several fixed cases.
• End each classic case with break to avoid fall-through.
• default handles values that match no case.
• Stacked cases can share one action on purpose.
• The modern arrow switch avoids break and can return a value.

Next, compare with if-else, or build a menu in the switch calculator.