[xwiki-users] Need Help rgarding customization of xwiki to suit my needs

As i earlier said i have my project web application on one tomcat instance and xwiki application on another tomcat instance. So when i click help link on my project web application it should take me to xwiki webapplication and whatever class i mentioned against xwiki.authentication.authclass should do the custom authentication. So,I downloaded the war file xwiki-enterprise-web-3.2 and started working on that. I have got some questions/issues while working on this. These are:- 1) Is it possible to get the source code of xwiki java files so that if want have detailed some understanding/or modification as per my requirements i can go ahead? After modification i will pack it with existing jar file and deploy it. 2) As i said in the begining i want custom authentication .So my question is what are interfaces/parent class my custome class should extend and with which library(jar file ) it should be packed with .how i can find it out? Is there any api doc like standard java docs something like this? Thanks in advance.