Local to UTC
DateTime dateTimeNew = new DateTime(date.getTime(),
DateTimeZone.forID("Asia/Calcutta"));
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
simpleDateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
String datetimeString = dateTimeNew.toString("yyyy-MM-dd HH:mm:ss");
long milis = 0;
try {
milis = simpleDateFormat.parse(datetimeString).getTime();
} catch (ParseException e) {
e.printStackTrace();
}