How to remove milliseconds from a timestamp?

Had same issue had my initial timestamp stored in sq and did sq.setTime(1000*(long)Math.floor(sq.getTime()/ 1000)); that does the job. In my case sq is a sql.Timestamp

If I understand you correctly there is no need to use Date / Calendar...

long yourmilliseconds = 1274883865399L;
long droppedMillis = 1000 * (yourmilliseconds/ 1000);    
System.out.println(droppedMillis);

1274883865000

Or... if you wish to have date formatting...

Calendar c = Calendar.getInstance();
c.setTime(new Date(yourmilliseconds));
c.set(Calendar.MILLISECOND, 0);
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm.ss.SSS'Z'");
sdf.setTimeZone(TimeZone.getTimeZone("GMT"));
System.out.println(sdf.format(c.getTime()));

2010-05-26T14:24.25.000Z