TimeZone and daylight savings time updates.

I'm wondering how java.util.TimeZone gets updated, if at all, when
governments change daylight savings time. They're talking about it
right now in the US Congress
http://news.yahoo.com/s/usatoday/20050722/pl_usatoday/daylightsavingextensiondrawsheatoversafetycost

How does the system deal with the following timezone lookup? Is it in
some sort of directory that gets updated with new versions of the jvm?

TimeZone tz = TimeZone.getTimeZone("America/Los_Angeles");

Right now I have an app that does everything in GMT, but I'll need to
get exact time in local time zones eventually.

Thanks.

.