public static TimeZone randomTimeZone(Random random){
  String tzIds[]=TimeZone.getAvailableIDs();
  return TimeZone.getTimeZone(tzIds[random.nextInt(tzIds.length)]);
}

public static TimeZone randomTimeZone ( Random random ) { String tzIds [ ] = TimeZone . getAvailableIDs ( ) ; return TimeZone . getTimeZone ( tzIds [ random . nextInt ( tzIds . length ) ] ) ; }
return a random timezone from the available timezones on the system
