Where's SQL error code???

Switching to postgres from mysql.  mysql jdbc driver returns
the sql error code to SQLWarning.getErrorCode()  (i.e.
insert with duplicate entry throws adn SQLException with
getErrorCode() = 1062).

Does anyone know where to get error codes in postgres (using
jdbc driver: pg73jdbc2ee.jar)?  I know table is set up
correctly because when I try to insert duplicate entry I
get "ERROR:  Cannot insert a duplicate key into unique
index ...".  An SQLException is thrown but getErrorCode()
is 0.

Thanks, any suggestion is much appreciated,
Ken