As you might know, Avatica is already migrated to Gradle. On top of that, Calcite is almost there as well: https://github.com/apache/calcite/pull/1571
The missing bit is probably the notion of tests "fast/slow/etc/etc". Unfortunately, there are tests that assert on folder layout like "target/test-classes". I'm going to ignore those tests for now, and fix them as pom.xml files are removed. I'm going to configure Gradle to use JUnit5 engine to run the tests. In the meantime, everybody's welcome to preview Gradle build. Vladimir
