code: public static String format(final long millis, final String pattern, final TimeZone timeZone) {
          return format(new Date(millis), pattern, timeZone, null);
      }
docs: <p>Formats a date/time into a specific pattern in a time zone.</p>
  
  @param millis  the time expressed in milliseconds
  @param pattern  the pattern to use to format the date, not null
  @param timeZone  the time zone  to use, may be <code>null</code>
  @return the formatted date