a lot java applications are build with maven. maven has Profiles concept, it is really handy to build release package for different environments. e.g. dev/test/prod
Maven profiles would provide a build-time solution, while SpringFramework profiles would provide a runtime alternative. I think this is the first question one may ask himself: if he wants to have a single package that can be deployed in different environments, or if he wants the build tool to provide different packages according to the destination environment.
One thing to keep in mind is that many questions may arise if you have different packages deployed into different servers. In my workplace, for example, if I am deploying a package to correct a bug previously occurred in production environment, a company policy would state that the only acceptable scenario is that I have the same solution package in QA and in production servers.