Java tutorial
import java.util.Calendar; public class Main { public static void main(String[] args) { Calendar cal = Calendar.getInstance(); // displays the current calendar System.out.println("Month is " + cal.get(Calendar.MONTH)); // roll month cal.roll(Calendar.MONTH, true); // print result after rolling System.out.println("Month is " + cal.get(Calendar.MONTH)); // roll downwards cal.roll(Calendar.MONTH, false); // print result after rolling down System.out.println("Month is " + cal.get(Calendar.MONTH)); } }