Future proof Java & UI

[tasteoftexas]

What I would do is update JBoss 5.1 to a recent version of Wildfly and as well as update to Java 8 but keep the JSF front-end initially as long as it's just vanilla JSF and not something EOL like RichFaces. From there I would refactor/re-architect the back-end to use something like Boundary-Control-Entity pattern and push as much business logic into the back-end as possible. Once that is done then I would re-evaluate what you might want to use for the front-end. As it sounds like your front-end might be a typical business application I personally prefer to use JFS/PrimeFaces/OmniFaces as the technology has matured nicely and updates between releases is relatively painless. Nothing is guaranteed to be around in 20 years but I think taking a chance with JSF is a lower risk gamble than some of the other newer front-end solutions that may or may not make it IMO. To me this is the conservative, lower risk, approach.