Python, Perl and Ruby all have expect or expectlike libraries.
I had not heard of JCAT so I googled it. Based on the search results...
I guess that it is not a hugely popular test automation tool.
Expect is a tool for automating interactive textual interfaces.
As far as I know for that particular problem Expect is the best solution.
Sorry I don't have stats.
Sincerely,
Russell Treleaven
ru...@else.net