We can create date/time values using the Calendar class.
We represent the date 20th May 1962 and print it.
We add 40 days to the date and print again.
Calendar.JANUARY is 0 rather than 1 as you might expect.
We can also add
Calendar.DAY_OF_MONTH
Calendar.MONTH
Calendar.YEAR
In printf we can use the codes:
%td day of month (two digit)
%tm month of year (two digit)
%tY year (four digit)
%ta day of week (three characters)