why does extract ( HOUR FROM TIMESTAMP '2010-01-01 00:00:00' at time zone 'utc' ) == 16?

Is this the correct behavior? It seems like if I specify the utc offset it
should be 0, not 16.. It seems to be the opposite behavior from extract
epoch.

select extract ( HOUR FROM TIMESTAMP '2010-01-01 00:00:00' ) as defhour,
extract ( HOUR FROM TIMESTAMP '2010-01-01 00:00:00' at time zone 'PST' ) as
psthour, extract ( HOUR FROM TIMESTAMP '2010-01-01 00:00:00' at time zone
'utc' ) as utchour, extract ( epoch FROM TIMESTAMP '2010-01-01 00:00:00' at
time zone 'utc' ) as utcepoch;

0,0,16,1262304000

@Test
public void testFoo() {
TimeZone tz = TimeZone.getTimeZone("GMT");
GregorianCalendar cal = new GregorianCalendar(tz);
cal.set(2010,0,1,0,0,0);
cal.set(GregorianCalendar.MILLISECOND, 0 );
System.out.println("" + cal.getTimeInMillis() );
System.out.println("" + String.format( "%1$tY-%1$tm-%1$td
%1$tH:%1$tM:%1$tS.%1$tL", cal ) );
System.out.println("" + cal.get(GregorianCalendar.HOUR_OF_DAY ) );
}

In Java:
1262304000000
2010-01-01 00:00:00.000 (UTC)
0