There are a few java-interop test failures when building Clojure under Java 12. Attached patch fixes these in a backward compatible way and should be less susceptible to new breakage with future Java versions.
test-bases: check that expected are a subset of the bases found (Java 12 finds some additional new interfaces)
test-supers: same thing
test-proxy-non-serializable: has per-Java serialized proxies. Added a Java 12 proxy and replaced test failure with a warning message to alert it should be updated (doesn't need to fail the build on a new version).