How to get current time for timezone

I have UTC time offsets for specific operations stored like this: (this one is for UTC+2)

double utc = 2.0;

How can I get current time for that timezone using this double time offset in Java?

You may combine

• ZoneOffset.ofTotalSeconds to get the offset zone from the hour offset
• Instant.atOffset to get the OffsetDatetime from current Instant and the ZoneOffset

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OffsetDateTime odt = Instant.now().atOffset(ZoneOffset.ofTotalSeconds((int) (2.0*3600)));

Code Demo

First you need to convert the double value to a ZoneOffset:

double utc = 2.0;

ZoneOffset offset = ZoneOffset.ofTotalSeconds((int) (utc * 3600));

You can then get the current time:

OffsetDateTime now = Instant.now().atOffset(offset);

Sample Output

2020-09-22T21:16:42.816236600+02:00

Two other alternatives:

Using:

double utc = 2.0;

Alternative 1:

ZonedDateTime nowAlt1 = Instant.now().atZone(ZoneOffset.ofTotalSeconds((int) utc * 3600));

Alternative 2:

 ZonedDateTime nowAlt2 = ZonedDateTime.ofInstant(Instant.now(), ZoneOffset.ofTotalSeconds((int) utc * 3600));

Alternative 1 and 2 in context:

public static void main(String[] args) {
    double utc = 2.0;
    ZonedDateTime nowAlt1 = Instant.now().atZone(ZoneOffset.ofTotalSeconds((int) utc * 3600));
    ZonedDateTime nowAlt2 = ZonedDateTime.ofInstant(Instant.now(), ZoneOffset.ofTotalSeconds((int) utc * 3600));

    System.out.println("nowAlt1: " + nowAlt1);
    System.out.println("nowAlt2: " + nowAlt2);
}

Output:

nowAlt1: 2020-09-22T23:15:00.254912800+02:00
nowAlt2: 2020-09-22T23:15:00.253915600+02:00

Read more about java.time here, will give you an idea when to use the different types of java.time:
https://stackoverflow.com/questions/32437550/whats-the-difference-between-instant-and-localdatetime