Multiple-user web application client authentication Sample

[christophe peixoto]

I am trying to make an authentication in my web application (make in 
Java\Gwt) but i dont really know how.
 
Can someone give me a sample of how i must do the AuthSub
I have read the developer's guide,but i didt quite get it since i am knew 
both with GWT\Webapplications and this API
 
an example would help me a lot
Thank You