String inputStr = "Dec 12, 2013 1:54:03 AM PST";
SimpleDateFormat sdf = new SimpleDateFormat("MMM d, yyyy K:m:s a",Locale.ENGLISH);
SimpleDateFormat sdf2 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Date date1;
String date2;
try {
date1 = sdf.parse(inputStr);
System.out.println(date1);
date2 = sdf2.format(date1);
System.out.println(date2);
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}