[jboss-user] [Security & JAAS/JBoss]

I am trying to configure DatabaseServerLoginModule for my web application. I have login page with user name and password when click on submit what should happen I am having one basic question. So when I click on submit, will JBoss check for credentials or we have to check against the database programatically. please let me know I am new to this. please help. please also send me the sample code if you have for authentication and authroization using JBoss. regards