As you can tell, I am a maven power user. I use it for most of my projects (sometimes we run into pure Eclipse, Gradle and Ant).
I started work on porting one version of the exact version of one model to a new version of the same model (same classes). I need to use both JARs in the same classpath. This leads to a problem – how to use both at the same time.
I like to use the maven-shade-plugin and relocate the class files such that package.class-file is relocated to package.old.class-file. Generally this works well (except where you use reflexsive pathing in Class.forName to look up a class). I was able to prepend a string before shading the class.
The pom.xml I used is much like the attached project. I hope this helps you all.