Java Language Time Zones and java.util.Date


Example

A java.util.Date object does not have a concept of time zone.

  • There is no way to set a timezone for a Date
  • There is no way to change the timezone of a Date object
  • A Date object created with the new Date() default constructor will be initialised with the current time in the system default timezone

However, it is possible to display the date represented by the point in time described by the Date object in a different time zone using e.g. java.text.SimpleDateFormat:

Date date = new Date();
//print default time zone
System.out.println(TimeZone.getDefault().getDisplayName());
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); //note: time zone not in format!
//print date in the original time zone
System.out.println(sdf.format(date));
//current time in London
sdf.setTimeZone(TimeZone.getTimeZone("Europe/London"));
System.out.println(sdf.format(date));

Output:

Central European Time
2016-07-21 22:50:56
2016-07-21 21:50:56