How can I prevent Joda Time throwing an exception during Brazilian DST transition period

Question

Today our Brazilian users are generating plenty of crash reports for us. I've tracked it down to this code, which throws a Joda exception:

import org.joda.time.DateTime;
import org.joda.time.DateTimeUtils;
import org.joda.time.DateTimeZone;
import org.joda.time.LocalTime;

public class ScratchSpace {

    public static void main(String[] args) {
        // force Joda to act like we are in Sao Paolo on 2015-10-18
        DateTimeUtils.setCurrentMillisFixed(1445185758078L); // 2015-10-18T18:29
        DateTimeZone.setDefault(DateTimeZone.forID("America/Sao_Paulo"));

        // most of users have offset == 0, but it could be any number of millis from 0 to 86_400_000-1 (millis in day) 
        int offset = 0;

        // local time at start of day + offset millis  
        final LocalTime localTime = LocalTime.fromMillisOfDay(offset);

        // convert to a time on the current day
        DateTime dateTime = localTime.toDateTimeToday();  // throws org.joda.time.IllegalFieldValueException exception
        System.out.println("dateTime = " + dateTime);
    }
}

The exception:

Exception in thread "main" org.joda.time.IllegalFieldValueException: Value 0 for hourOfDay is not supported: Illegal instant due to time zone offset transition (daylight savings time 'gap'): 2015-10-18T00:29:18.078 (America/Sao_Paulo)
    at org.joda.time.chrono.ZonedChronology$ZonedDateTimeField.set(ZonedChronology.java:486)
    at org.joda.time.chrono.BaseChronology.set(BaseChronology.java:240)
    at org.joda.time.LocalTime.toDateTimeToday(LocalTime.java:1287)
    at org.joda.time.LocalTime.toDateTimeToday(LocalTime.java:1270)

I'm using Java 1.8.0_60 on OS X 10.11 with Joda Time 2.8.2.

What work-around will allow me to correctly get a DateTime instance representing a time on the current day that is offset milliseconds after the start of the day?

Answer 1

Don't go though a LocalTime. Create a DateTime, and add the offset in milliseconds:

DateTime startOfDay = LocalDate.now().toDateTimeAtStartOfDay();
DateTime dateTime = startOfDay.plus(offset);

System.out.println("dateTime = " + dateTime);