Actually... deploying two war copies would cause the app server to create and run two separate applications, right? Which would mean any application scoped state, like app scoped beans or singleton objects or whatever would not be shared between the two apps? That would be a pretty different situation than running the same app with the same state at two different context roots if there is much app scoped state...
At this stage in my project I actually don't know if there will be though, and in any case I guess forwarding requests from one context root to the other would be an ok solution. So I'll mark this answered.
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