> I'd like to turn up my internal sense of skepticism when dealing with someone, effectively, selling something their salary depends on

This is really, really silly. Java is many times beyond the position where its developers need to desperately convince people to use it. This is a person who has unique technical expertise in the area whose credentials are smack dab on their profile, not hidden from you. Their closeness to the domain at hand should make you less skeptical of what they are saying.