Mar 12, 2017 02:39:00 "America/Chicago" does not exist. When I set the date and time to this value it does not fail. The time gets set to Mar 12, 2017 03:39:00 an hour later. How can I be notified that this time does not exist. Here is how the time skips forward
01:59:59
3:00:00
As you can see 02:39:00 will never exist on this date.
Here is the code I am using
package com.company;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZoneOffset;
import java.time.ZonedDateTime;
public class Main {
public static void main(String[] args) {
ZoneId zoneId = ZoneId.of("America/Chicago");
ZonedDateTime dateTimeStart = ZonedDateTime.of(2017, 1, 1, 15, 39, 0, 0, ZoneId.of("America/Chicago"));
ZonedDateTime dateTimeStartUtc = dateTimeStart.withZoneSameInstant(ZoneOffset.UTC);
ZoneId zoneIdDst = ZoneId.of("America/Chicago");
ZonedDateTime dateTimeStartDst = ZonedDateTime.of(2017, 3, 12, 2, 39, 0, 0, ZoneId.of("America/Chicago"));
ZonedDateTime dateTimeStartUtcDst = dateTimeStart.withZoneSameInstant(ZoneOffset.UTC);
int y = 90;
}
}
Your sample doesn't throw an exception because ZonedDateTime.of(..) adjusts the date time. The javadoc states
This creates a zoned date-time matching the input local date-time as closely as possible. Time-zone rules, such as daylight savings, mean that not every local date-time is valid for the specified zone, thus the local date-time may be adjusted.
You could use ZonedDateTime#ofStrict(LocalDateTime, ZoneOffset, ZoneId) to perform the validation.
Obtains an instance of ZonedDateTime strictly validating the combination of local date-time, offset and zone ID.
This creates a zoned date-time ensuring that the offset is valid for the local date-time according to the rules of the specified zone. If the offset is invalid, an exception is thrown.
You'll first need to construct a LocalDateTime. Then you'll get the ZoneOffset for your ZoneId for that local date time. Then you can provide all three to ofStrict.
For example,
ZoneId zoneId = ZoneId.of("America/Chicago");
LocalDateTime ldt = LocalDateTime.of(2017, 3, 12, 2, 39, 0, 0);
ZoneOffset zoneOffset = zoneId.getRules().getOffset(ldt);
ZonedDateTime zdt = ZonedDateTime.ofStrict(ldt, zoneOffset, zoneId);
would throw
Exception in thread "main" java.time.DateTimeException: LocalDateTime '2017-03-12T02:39' does not exist in zone 'America/Chicago' due to a gap in the local time-line, typically caused by daylight savings
at java.time.ZonedDateTime.ofStrict(ZonedDateTime.java:484)