Eric Burke: "A few years back, we had a case where a 3rd party library had embedded JDOM beta 8 into their JAR, but they did not change the package names. When we tried updating our applications to JDOM 1.0, we ran into conflicts because the old JDOM was embedded into one of the JAR files we needed. This is exactly the kind of problem that Jar Jar Links can eliminate."
If there was a single thing I wish jar/war files had it'd be this - a "conf" standard folder. That way sysadmins could stay sane while managing a configuration that wasn't sourced from the build itself. Not all of us are running container middleware.