It's a matter of semantics. "A Java application" is perfectly honest. Just like when someone says "a native application" it says nothing about if it was actually written in OCaml.
Stuff like that tends to have consequences, especially when there are contracts and liabilities involved.
Also, if you're hiring programmers who can't pick up a new language to work on your project, you're doing it wrong. Most of the capable folks I've worked with loved learning new tech; the problem is usually keeping them from jumping onto a new platform for every project.