Java Gregorian calendar time zone

I have a strange question about Java Gregorian calendar:

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:S Z");
sdf.setTimeZone(TimeZone.getTimeZone("US/Pacific"));

GregorianCalendar cal1 = new GregorianCalendar(TimeZone.getTimeZone("US/Pacific"));
cal1.setTimeInMillis(1320566400000L);

GregorianCalendar cal2 = new GregorianCalendar(TimeZone.getTimeZone("US/Pacific"));
cal2.setTimeInMillis(1320570000000L);

System.out.println(sdf.format(cal1.getTime()));
System.out.println(sdf.format(cal2.getTime()));

I executed the code given above on the machine with default time zone = US Pacific, but the machine is running in Germany

The results are as follows:

2011-11-06 01:00:00:0 -0700
2011-11-06 01:00:00:0 -0800

I really don't understand why there are different time zones in the results... I also tested the code on another machine (default time zone = GMT), and it works normally

Someone has an idea. Why is this problem?

Best, Michael

Solution

Add these lines to your program:

for (int i=0; i<24; i++) {
    cal1.add(Calendar.MINUTE,i*5);
    System.out.println(" : " + sdf.format(cal1.getTime()));
}

You will see:

: 2011-11-06 01:00:00:0 -0700
 : 2011-11-06 01:05:00:0 -0700
 : 2011-11-06 01:15:00:0 -0700
 : 2011-11-06 01:30:00:0 -0700
 : 2011-11-06 01:50:00:0 -0700
 : 2011-11-06 01:15:00:0 -0800
 : 2011-11-06 01:45:00:0 -0800
 : 2011-11-06 02:20:00:0 -0800
 : 2011-11-06 03:00:00:0 -0800

So it seems that you are changing daylight saving time to winter My time zone is CET (UTC 01:00), so I don't understand why it works on your second machine