One of the post I read that, replacing UI layer or other layers are easy since Seam is an integration framework. How easy it is? does it involve more XML configurations? Is there any guidelines or resources you can suggests for this purpose?
Basically you don't need an extra UI layer when using Seam. You can bind JSF components directly to POJOs or EJBs which inject the EntityManager directly to perform DB operations. This avoids an extra UI layer and you can avoid the addition of DAOs. This may not be feasible in all cases, but can greatly simplify your application.