[SOLVED] Given ISO and timezone strings, how to convert them to UTC string in Java?

Given ISO and timezone strings, how to convert them to UTC string in Java?

For example, I have an ISO string "2022-12-22T18:20:00.000", and a timezone string "US/Eastern". How do I convert them into a UTC time in the same format (iso 8601), using Java?

Solution

** Update **

A better version, thanks to Arvind's response below.

    final ZonedDateTime americaNewYork =
            LocalDateTime.parse("2022-12-22T18:20:00.000")
                         .atZone(ZoneId.of("America/New_York"));
    final Instant utc = americaNewYork.toInstant();

First Pass

I'm not at a computer where I can test this but I think this might do the trick...

    final ZonedDateTime usEastern =
            LocalDateTime.parse("2022-12-22T18:20:00.000", DateTimeFormatter.ISO_DATE_TIME)
                         .atZone(ZoneId.of("US/Eastern"));
    final ZonedDateTime utc = usEastern.withZoneSameInstant(ZoneId.of("UTC"));