Java: Customize adding 1 month to the current date

Question

I\'ve read around and basically I\'ve figured out that the Calendar object is capable of adding 1 month to a date specified by using something like:

Calendar         


        

Answer 1

What you are asking for is some implicit knowledge that if the starting date is the last day of the month, and you add 1 month, the result should be the last day of the following month. I.e. the property "last-day-of-month" should be sticky.

This is not directly available in Java's Calendar, but one possible solution is to use Calendar.getActualMaximum(Calendar.DAY_OF_MONTH) to reset the day after incrementing the month.

Calendar cal = ...;
cal.add(Calendar.MONTH,1);
cal.set(Calendar.DAY_OF_MONTH,cal.getActualMaximum(Calendar.DAY_OF_MONTH));

You could even subclass GregorianCalendar and add a method

public Calendar endOfNextMonth() { ... }

to encapsulate the operation.