How to get the first date and last date of current quarter in java.util.Date

Question

I need to get the first date of the current quarter as a java.util.Date object and the last date of the current quarter as a java.util.Date

Answer 1

Keep it simple

I think the following is most elegant because it doesn't have any magical numbers (like 92), TemporalAdjusters or non-obvious calculations, and can easily be adapted to get the start and end of any quarter (not just current quarter).

import static java.time.temporal.IsoFields.QUARTER_OF_YEAR;

LocalDate date = LocalDate.now(); // can be any other date

int year = date.getYear();
int quarter = date.get(QUARTER_OF_YEAR);
        
LocalDate start = YearMonth.of(year, 1)                    // January of given year
                           .with(QUARTER_OF_YEAR, quarter) // becomes first month of given quarter
                           .atDay(1);                      // becomes first day of given quarter

LocalDate end = YearMonth.of(year, 3)                      // March of given year
                         .with(QUARTER_OF_YEAR, quarter)   // becomes 3rd (last) month of given quarter
                         .atEndOfMonth();                  // becomes last day of given quarter

If you don't have a date, but just a year and quarter (e.g. Q2 2020), this becomes:

LocalDate start = YearMonth.of(2020, 1).with(QUARTER_OF_YEAR, 2).atDay(1);
LocalDate end = YearMonth.of(2020, 3).with(QUARTER_OF_YEAR, 2).atEndOfMonth();