Potential circular dependency in JRuby

Hello,

Lately I've been working in updating JRuby in Debian to the new 9.4 
release series.

As part of this work, I hoped to reduce the maintenance burden by 
greatly simplifying debian/rules and reducing the scope of required 
patches. By packaging both polyglot-ruby and jruby-mavengem (which I 
have completed) and making them available to the Maven build process, I 
was able to achieve this.

However, since both of these new binary packages rely on JRuby to 
function, I been warned that this circular dependency may cause problems 
in the future.

So my question is, what kinds of practical problems might this cause? 
Bootstrapping new Debian ports shouldn't be affected, since all packages 
involved are arch:all.

Thanks!

-- Jérôme