How to use roll(int field, boolean up) method of Java.util.GregorianCalendar class

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GregorianCalendarDemo.java

import java.util.GregorianCalendar;

public class GregorianCalendarDemo
{
    public static void main(String[] args)
    {
        GregorianCalendar cal = (GregorianCalendar) GregorianCalendar
                .getInstance();

        System.out.println("Date = "+cal.getTime());

        /*
         * Parameters:
         *
         * field - the time field.
         *
         * up - indicates if the value of the specified calendar field
         * is to be rolled up or rolled down. Use true if rolling up,
         * false otherwise.
         */
        // roll a month forward
        cal.roll(GregorianCalendar.MONTH, true);
        System.out.println("Date = " + cal.getTime());

        // roll a year backwards
        cal.roll(GregorianCalendar.YEAR, false);
        System.out.println("Date = " + cal.getTime());
    }
}

Output

Date = Wed Oct 10 09:09:11 IST 2018
Date = Sat Nov 10 09:09:11 IST 2018
Date = Fri Nov 10 09:09:11 IST 2017

Click the below link to download the code:
https://sites.google.com/site/ramj2eev2/java_basics/GregorianCalendarDemo_roll_up_indicator.zip?attredirects=0&d=1

Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava_2018/GregorianCalendarDemo_roll_up_indicator

Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/4cfac93378c4f9d33f18bb5083115d18778294de/BasicJava_2018/GregorianCalendarDemo_roll_up_indicator/?at=master

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