Setting time zone of a java util Date

Question

Can someone help me in specifying the time zone of a date object that I have parsed from a String?
The timezone is not specified in the String but by default, it is setting the local time zone as the time zone of the date object. Please suggest.

Answer 1

You can make use of the following DateFormat.

SimpleDateFormat myDate = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");
myDate.setTimeZone(TimeZone.getTimeZone("UTC"));
Date newDate = myDate.parse("2010-05-23T09:01:02");

You need to do this because by default java.util.Date objects do not contain any timezone information.

Answer 2

Be aware that java.util.Date objects do not contain any timezone information by themselves - you cannot set the timezone on a Date object. The only thing that a Date object contains is a number of milliseconds since the "epoch" - 1 January 1970, 00:00:00 UTC.

As ZZ Coder shows, you set the timezone on the DateFormat object, to tell it in which timezone you want to display the date and time.

Answer 3

Using Java 8

Java 8 introduced a new Date-Time API for working with dates and times which was largely based on the Joda-Time library.

The Instant class from Java Date Time API models a single instantaneous point on the timeline in UTC. This represents the count of nanoseconds since the epoch of the first moment of 1970 UTC.

First, we'll obtain the current Instant from the system clock and ZoneId for a time zone name:

Instant nowUtc = Instant.now();
ZoneId asiaSingapore = ZoneId.of("Asia/Singapore");

Finally, the ZoneId and Instant can be utilized to create a date-time object with time-zone details. The ZonedDateTime class represents a date-time with a time-zone in the ISO-8601 calendar system:

ZonedDateTime nowAsiaSingapore = ZonedDateTime.ofInstant(nowUtc, asiaSingapore);

We've used Java 8's ZonedDateTime to represent a date-time with a time zone.

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