We also need to get "rat" to run on the content of the source tarball. This is currently done by Java's build.xml. We could leave that there.
That is probably the easiest thing to do, unless maven's RAT plugin works with the exclusion list easily. I got it working quickly on the Java tree, but it complains about a few things that need to be excluded. Does the current java ant task run RAT for all languages? If so, it should remain an ant task since Maven won't run RAT outside of its directory tree.
As you indicate above, we might also keep driving the interop tests with Ant. The complication I see is building an appropriate classpath that includes the dependencies. Any ideas of how to do that? Should we have Ivy read the pom files and download the jars? Is there a way to get Maven to put all the dependencies in a directory?
We could, but it might be easier to use the Maven facilities for this. It is easy to have it copy all the dependent jars in one place. Or, we can use the 'failsafe' plugin to run the interop tests as integration tests. Or, configure a profile with them as a separate set of Unit tests with surefire and activate that profile from the command line after the build "mvn test -P interop". I am planning on working on this ticket early next week, along with the other main tasks to complete the maven migration.