java.util.Date - Deleting three months from a date?

Question

I have a date of type java.util.Date

I want to subtract three months from it.

Not finding a lot of joy in the API.

Answer 1

Using Java 8 you can do it like this,

Date d = Date.from(LocalDate.now().minusMonths(3).atStartOfDay(ZoneId.systemDefault()).toInstant());

The LocalDate class has a lot of methods to help you make easy computations about dates like the above,

// Add 2 months
Date d = Date.from(LocalDate.now().plusMonths(2).atStartOfDay(ZoneId.systemDefault()).toInstant());
// Add 5 days
Date d = Date.from(LocalDate.now().plusDays(5).atStartOfDay(ZoneId.systemDefault()).toInstant());
// Minus 1 day and 1 year
Date d = Date.from(LocalDate.now().minusYears(1).minusDays(1).atStartOfDay(ZoneId.systemDefault()).toInstant());

In order to compute time you can use the LocalDateTime class,

// Minus 1 year, minus 1 days, plus 1 hour
Date d = Date.from(LocalDateTime.now().minusYears(1).minusDays(1).plusHours(1).toLocalDate().atStartOfDay(ZoneId.systemDefault()).toInstant());