SimpleDateFormat: hours are HH after parsing

I have a String which is 2013-8-25, 16:33, now I need to convert it into Date. For this purpose I use:

Date mDate = new SimpleDateFormat("yyyy-MM-dd, HH:mm").parse("2013-8-25, 16:33");

Then I need to get a String of proper pattern, which is

private static final String DATE_PATTERN = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'";

and here is how I do it:

  public static String convertDateToString(Date date) {
        String string = DateFormat.format(DATE_PATTERN, date).toString();
        Logger.logVerbose(TAG, "Date converted into String is " + string);
        return string;
    }

but:

Date converted into String is 2013-08-25THH:33:00.SSSZ

Why hours are still HH? Thanks!