Train on java compiled to class files. Then go from class back to java.
Or even:
Train java compiled to class files, and have separate models that train from Clojure to class and Scala to class files. Then see if you can find some crufty (but important) old java project and go: crufty java -> class -> Clojure (or Scala).
If you could do the same with source -> machine instructions, maybe COBAL to C++! or whatever.
Train on java compiled to class files. Then go from class back to java.
Or even:
Train java compiled to class files, and have separate models that train from Clojure to class and Scala to class files. Then see if you can find some crufty (but important) old java project and go: crufty java -> class -> Clojure (or Scala).
If you could do the same with source -> machine instructions, maybe COBAL to C++! or whatever.