re: naming. If you're someone like me who is becoming fairly familiar with using solr, but not with the solr code – then "SolrInfoMBeanHandler" or "admin/mbean" doesn't mean anything to me, and is kind of confusing. I want to get info on my indexes and caches-- it would be very non-obvious to me (if i hadn't read this ticket) that "MBean" has anything to do with this, since I don't know what an MBean is – and probably shouldn't have to to use solr through it's APIs.
So seems to me that a name based on the functions provided (not the underlying internal implementation) is preferable. But i recognize the namespace conflict problems, so much stuff in Solr already (some of it deprecated or soon to be deprecated or removed, some of it not) that it's hard to find a non-conflicting name.
Even if the underlying class is SolrInfoMBeanHandler, would it be less (or more) confusing for the path to be /admin/info still? That might be less confusing, as someone like me would still see /admin/info in the config and think, aha, that might be what I want. Or the lack of consistency might just be more confusing in the end.
I don't know what the current SystemInfoHandler does, what's the difference between that and this new one? There might be hints to naming in that. If the new one does everything the old one does, perhaps call it NewSystemInfoHandler, but still register it at /admin/info, with the other one being deprecated? Just brainstorming. Or rename the other one to OldSystemInfoHandler.