Regarding j_security_check

[Damnish]

Hi All,
       I am using tomcat 3.2 .and  using JDBCRealm for authintication, It is
working fine.
But has some minor issues. Can anyone tell me some documents where i can
read
inside of j_security_check , How exactly it work?
and where should  i make changes so that it work accoring to my needs.
Thanks and regards
Damnish