code: public final String format(Style style, TimeZone tz, long date) {
          return format(style, tz, date, null);
      }
docs: Returns the display name of the time zone at the given date for
  the style.
  
  <p><b>Note</b>: A style may have fallback styles defined. For example,
  when <code>GENERIC_LONG</code> is requested, but there is no display name
  data available for <code>GENERIC_LONG</code> style, the implementation
  may use <code>GENERIC_LOCATION</code> or <code>LOCALIZED_GMT</code>.
  See UTS#35 UNICODE LOCALE DATA MARKUP LANGUAGE (LDML)
  <a href="http://www.unicode.org/reports/tr35/#Time_Zone_Fallback">Appendix J: Time Zone Display Name</a>
  for the details.
  
  @param style the style enum (e.g. <code>GENERIC_LONG</code>, <code>LOCALIZED_GMT</code>...)
  @param tz the time zone.
  @param date the date.
  @return the display name of the time zone.
  @see Style
  @see #format(Style, TimeZone, long, Output)