Why do we need break after case statements?

Question

Why doesn\'t the compiler automatically put break statements after each code block in the switch? Is it for historical reasons? When would you want multiple code blocks to e

Answer 1

The break after switch cases is used to avoid the fallthrough in the switch statements. Though interestingly this now can be achieved through the newly formed switch labels as implemented via JEP-325.

With these changes, the break with every switch case can be avoided as demonstrated further :-

public class SwitchExpressionsNoFallThrough {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int value = scanner.nextInt();
        /*
         * Before JEP-325
         */
        switch (value) {
            case 1:
                System.out.println("one");
            case 2:
                System.out.println("two");
            default:
                System.out.println("many");
        }

        /*
         * After JEP-325
         */
        switch (value) {
            case 1 ->System.out.println("one");
            case 2 ->System.out.println("two");
            default ->System.out.println("many");
        }
    }
}

On executing the above code with JDK-12, the comparative output could be seen as

//input
1
// output from the implementation before JEP-325
one
two
many
// output from the implementation after JEP-325
one

and

//input
2
// output from the implementation before JEP-325
two
many
// output from the implementation after JEP-325
two

and of course the thing unchanged

// input
3
many // default case match
many // branches to 'default' as well