Not something we'll have to worry about for some time, but there's an interesting discussion happening on the dev@maven list about JEP 238: Multi-Version JAR files.
The main focus is on supporting alternate class implementations for different JVM versions, but the discussion has already extended to alternate versions of libraries. Too early to tell what fruit will come of it, but it could eventually give us some way better options for working across JVM / Hadoop versions without all the reflection. asf archive of start: http://s.apache.org/Fzx nabble thread: http://s.apache.org/i4d -- Sean