> I've seen XML configurability used as an extension point for code that would otherwise be closed.
Take a step back, and think why that 'extension point' had to be closed to begin with. You're probably going to find either an architectural flaw, or a problem with your tooling that should not have required this sort of thing in the first place.
Also disturbing is that you are using XML to add a degree of expressiveness missing from whatever tooling you are using.
Hmm. So small example on what I saw recently was being able to swap the authorization/authentication piece from hitting a service to users defined in XML for locally running the project. Architecture flaw? No. Problem in tooling? If you have a convincing enough argument, yeah. Does Spring feel like it lets you do too much in XML? Hell yes. It's awesome when it works. It feels too convoluted when you don't need it.
Take a step back, and think why that 'extension point' had to be closed to begin with. You're probably going to find either an architectural flaw, or a problem with your tooling that should not have required this sort of thing in the first place.
Also disturbing is that you are using XML to add a degree of expressiveness missing from whatever tooling you are using.