Which date class should I use in Java 8?

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Each one of the Date classes are for specific purposes:

  • If you want to use your Date in an SQL/JDBC context, use the java.sql.Timestamp.

  • java.util.Date is the old Java API, it is not thread safe, you can difficultly handle time zoning, and on the top of all, it is poorly designed: one simple uniformity is that months start from 1 while days start from 0.

  • java.time.LocalDateTime is an immutable date-time object that represents a date-time, often viewed as year-month-day-hour-minute-second, which you need exactly.

  • java.time.ZonedDateTime class stores all date and time fields, so you can use it to deal with values like:
    27th January 1990 at 15:40.30.123123123 +02:00 in the Europe/Paris time-zone.

To do your task, the ZonedDateTime class handles conversion from the local time-line of LocalDateTime to the instant time-line of Instant (which models a single instantaneous point on the time-line). The difference between the two time-lines, represented by a ZoneOffset, is the offset from UTC/Greenwich.

To calculate duration and period: there is the java.time.Duration which is a time-based amount of time, such as ‘20.5 seconds’, and java.time.Period, which is a date-based amount of time (like: 26 years, 2 months and 2 days).

To get max and min dates, you can use the Java 8 lambdas in something like:

Date maxDate = list.stream().map(yourInstance -> yourInstance.date).max(Date::compareTo).get();
Date minDate = list.stream().map(yourInstance -> yourInstance.date).min(Date::compareTo).get();

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