How to make date.getTime() returns UTC time?

Question

I have a Date object which represents a UTC time. When I use the method getTime() to get the long value of this object, the value returned corresponds to our local time (central US). What is the correct way to get the value back which corresponds to the original UTC time?

Thanks

Answer 1

getTime() returns "the number of milliseconds since January 1, 1970, 00:00:00 GMT", nothing more, nothing less (obviously, you have to create it correctly). You can format it however you want, starting with e.g. the GregorianCalendar(TimeZone) constructor.

Answer 2

The DateFormat class has a method for setting your preferred time zone, and there's a time zone class that has a setting for UTC time.

So, for example,

SimpleDateFormat sdf = new SimpleDateFormat();
sdf.setTimeZone(new SimpleTimeZone(SimpleTimeZone.UTC_TIME, "UTC"));
Date yourUtcDate = sdf.parse(yourOriginalDate);

Answer 3

java.util.Date has no concept of timezone. It simply holds time relative to epoch, which is Jan 1 1970 00:00:00 UTC. Date is a model, separate from the view. You when display the date, the concept of timezone then is used. Date's toString() displays a human readable date in the default timezone. You can either use a DateFormat to display a Date in a different timezone (such as UTC), or change the JVM's default timezone.