#managedbean

@ManagedBean @SessionScoped public class UserController {

private Users user;

@EJB private UserService userservice;

   public String auth() {

// you have to implement your "authentificate" Function

       user = userservice.authentificate(username, password);

   if(user == null){     //Check if user exist's in database !!!!           return null;

      }else {               return "Dash";        }

}        

}

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@ManagedBean public class CarsController {

   @ManagedProperty(value="#{userController}")    private UserController userController;

===> you can access from here to the user and he is stored in Session

}

Common Error :

You can't Use Session Scoped Annotation And use in the same page ===> FacesContext.getCurrentInstance().getExternalContext().getSessionMap().put("key",user);