I agree with Helmut's suggestion that jruby should drop the Provides. Even if there are contexts in which jruby could act as a ruby interpreter, I don't think we should encourage our users to use it when we have ruby available. Or put another way, if you're using jruby, it typically to solve a specific problem or because you have special considerations about your runtime environment, not because you're looking for a general purpose Ruby interpreter.
If there are no objections, I'll prepare an upload of jruby that drops the Provides of ruby-interpreter.