Java Calendar roll() Method
The roll () method of Calendar class increases or decreases the specified calendar field by one unit without affecting the other field. For example, if the YEAR field is passed as the parameter. It will roll only the YEAR field. The roll() method is overloaded as roll(int field, int amount) in which, the amount of time is passed to roll the specified field by that amount of time.
field - the calendar field.
up - indicates if the value of the specified time field is to be rolled up or rolled down. Use true if rolling up, false otherwise.
Example 1Test it Now
Date : Tue Aug 14 17:38:23 PDT 2018 Date after rolling : Sun Sep 08 17:38:23 PDT 2019
Example 2Test it Now
Date : Tue Aug 14 17:42:25 PDT 2018 Date after rolling : Sun Oct 10 19:51:28 PDT 2027