This change to getLocalTimeAsString(…) in class SolarEventCalculator appears to do it:-

private String getLocalTimeAsString(BigDecimal localTime) {
String[] timeComponents = localTime.toPlainString().split(“\.”);
int hour = Integer.parseInt(timeComponents[0]);

BigDecimal minutes = new BigDecimal(“0.” + timeComponents[1]);
minutes = minutes.multiply(BigDecimal.valueOf(60)).setScale(0, RoundingMode.HALF_EVEN);
if (minutes.intValue() == 60) {
minutes = BigDecimal.ZERO;
hour += 1;
}

if(hour < 0 && minutes == BigDecimal.ZERO) hour += 24;
if(hour < 0) {
hour += 23;
int myMin = minutes.intValue();
myMin = 60 – myMin;
minutes = BigDecimal.valueOf(myMin);
}
String minuteString = minutes.intValue() < 10 ? “0″ + minutes.toPlainString() : minutes.toPlainString();
String hourString = (hour < 10) ? “0″ + String.valueOf(hour) : String.valueOf(hour);
return hourString + “:” + minuteString;
}

I forgot to mention that currently I am in NZ and we are 13 hours ahead of Zulu time.

Current date is good for causing the error mentioned.
Just ran a test now and sunrise reported 0-5:31
with this code appended to your Test.java :-

String sunrise = mySunriseCalc.getOfficalSunriseForDate(t);
System.out.println(“Sunrise is: ” + sunrise);
System.out.println(“Calendar is: ” + t.toString());
System.out.println(“Location is: ” + myLoc.getLatitude().toPlainString() + “, ” + myLoc.getLongitude().toPlainString());

produced:-

Sunset is: 06:50
Sunrise is: 0-5:34
Calendar is: java.util.GregorianCalendar[time=1268772592184,areFieldsSet=true,areAllFieldsSet=true,
lenient=true,zone=sun.util.calendar.ZoneInfo[id="GMT",offset=0,dstSavings=0,useDaylight=false,
transitions=0,lastRule=null],firstDayOfWeek=1,
minimalDaysInFirstWeek=1,ERA=1,YEAR=2010,MONTH=2,
WEEK_OF_YEAR=12,WEEK_OF_MONTH=3,DAY_OF_MONTH=16,
DAY_OF_YEAR=75,DAY_OF_WEEK=3,DAY_OF_WEEK_IN_MONTH=3,
AM_PM=1,HOUR=8,HOUR_OF_DAY=20,MINUTE=49,SECOND=52,
MILLISECOND=184,ZONE_OFFSET=0,DST_OFFSET=0]
Location is: -43.47, 172.55

Croques

As for the error case, can you specify a date that causes the error condition to occur so I can write a test around it?

Also note the inconsistent spelling of Official in getOfficalSunriseForDate.

Croques.