NewSwitch.java

import static java.util.Calendar.*;

public class NewSwitch {

    public static void main(String[] args) {
        int numberOfDays = getNumberOfDays(MARCH);
        System.out.println("The number of days in this month are " + numberOfDays);
    }


    public static int getNumberOfDays(int monthNum) {
        return switch (monthNum) {
            case JANUARY, MARCH, MAY, JULY, AUGUST, OCTOBER, DECEMBER -> 31;
            case APRIL, JUNE, SEPTEMBER, NOVEMBER -> 30;
            case FEBRUARY -> 28; //assuming nin leap year for simplicity
            default -> throw new IllegalArgumentException("Not a month");
        };
    }

}