I'm learning Seam at a very slow pace (because my company wants me to use gwt) so I just read about Seam, not writing any example. I notice that there some (maybe a lot) JSF components in Seam like calendar, file upload, .... and Seam even has something like the JSF core f tags (s:convertDateTime ....).

So why are there 2 different set of JSF components in the same company (which is JBoss)? Do they work well in the same xhtml page (if I use facelets)?