1. Only MyFaces in your list is a JSF implementation. Seam 1.2.1 uses MyFaces by default, Seam 2.x uses the JSF reference implementation (RI) from Sun. 1.1. The JSF RI. 2. It's the same thing, a templating solution that works particularly well with JSF. 3. Seam 1.2.1: JBoss AS 4.0.5 GA, Seam 2.x: JBoss AS 4.2.x 4. All? 5. Yes. Use Seam 2.x. and JBoss AS 4.2.1. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4095113#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...