CORBA
CORBA is a typical example of what I mentioned in the other thread. Many companies end up wanting to use CORBA (or requiring it for whatever reason), so they implement it and things seem dandy. A year down the line, they realise that things aren't working so well anymore, and after digging they determine that the implementation was poor. Thus, the implementation has to be revised, requiring more admin and time and money. If you have a track record of doing things like this (pretty simple) and doing it properly, that's a very marketable skill.
The most impressive "skill" that a prospective developer can showcase is agility.
I don't mean in terms of software development methodologies, but in terms of evolving with technology, learning what's new, what it can offer and how to leverage the advantages for the benefit of the organisation while still maintaining knowledge of legacy technologies that will always be around (for whatever reason).
Other than this, the question is very open ended and is highly organisation-dependent.
If you (or whoever you're asking for) already has some Java experience, then you (or whoever you're asking for) should already have an idea of what is used in practice and what is desirable from an employer's perspective.
