Round minutes to ceiling using Java 8

The java.time API does not support rounding to ceiling, however it does support rounding to floor (truncation) which enables the desired behaviour (which isn’t exactly rounding to ceiling):

LocalDateTime now =  LocalDateTime.now();
LocalDateTime roundFloor =  now.truncatedTo(ChronoUnit.MINUTES);
LocalDateTime roundCeiling =  now.truncatedTo(ChronoUnit.MINUTES).plusMinutes(1);

In addition, there is a facility to obtain a clock that only ticks once a minute, which may be of interest:

Clock minuteTickingClock = Clock.tickMinutes(ZoneId.systemDefault());
LocalDateTime now =  LocalDateTime.now(minuteTickingClock);
LocalDateTime roundCeiling =  now.plusMinutes(1);

This clock will automatically truncate minutes to floor (although it is specified such that it may return a delayed cached value). Note that a Clock may be stored in a static variable if desired.

Finally, if this is a common operation that you want to use in multiple places, it is possible to write a library TemporalAdjuster function to perform the rounding. (Adjusters can be written once, tested, and made available as a static variable or method).