SimpleDateFormat cannot parse milliseconds with more than 4 digits

I want to parse a timestamp, like this - "2016-03-16 01:14:21.6739". But when I use the SimpleDateFormat to parse it, I find that it outputs an incorrect parsed value. It will covert 6739 milliseconds to 6 seconds with 739 millseconds left. It converted the date to this format - Wed Mar 16 01:14:27 PDT 2016. Why the seconds part has changed from 21 seconds to 27 seconds(an addition of 6 seconds?). The following is my code snippet:

final SimpleDateFormat sf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSSS");
String parsedate="2016-03-16 01:14:21.6739";
try {
    Date outputdate = sf.parse(parsedate);
    String newdate = outputdate.toString();  //==output date is: Wed Mar 16 01:14:27 PDT 2016 
    System.out.println(newdate);
} catch (ParseException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}