Converting UTC dates to other timezones

It turns out the code was almost correct, what I didn't take into account was that when parsing the String to get a Date object initially, it uses default system TimeZone, so the source date was not in UTC as I expected.

The trick was to set the timezone when parsing the date to UTC and then set it to destination TimeZone. Something like this:

SimpleDateFormat sourceFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
sourceFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
Date parsed = sourceFormat.parse("2011-03-01 15:10:37"); // => Date is in UTC now

TimeZone tz = TimeZone.getTimeZone("America/Chicago");
SimpleDateFormat destFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
destFormat.setTimeZone(tz);

String result = destFormat.format(parsed);

Converting a date String of the format "2011-06-23T15:11:32" to out time zone.

 private String getDate(String dateString) {
    SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");
    formatter.setTimeZone(TimeZone.getTimeZone("UTC"));
    Date value = null;
    try {
        value = formatter.parse(dateString);
    } catch (ParseException e) {
        e.printStackTrace();
    }
    SimpleDateFormat dateFormatter = new SimpleDateFormat("dd/MM/yyyy hh:mmaa");
    dateFormatter.setTimeZone(TimeZone.getDefault());
    String dt = dateFormatter.format(value);

    return dt;
}

Following code works fine for me to change a date from one tz to another. It considers the DayLightSaving also.

public static Calendar changeTimezoneOfDate(Date date, TimeZone fromTZ, TimeZone toTZ) {
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(date);
    long millis = calendar.getTimeInMillis();
    long fromOffset = fromTZ.getOffset(millis);
    long toOffset = toTZ.getOffset(millis);
    long convertedTime = millis - (fromOffset - toOffset);
    Calendar c = Calendar.getInstance();
    c.setTimeInMillis(convertedTime);
    return c;
}