Seems like the root cause is that my JarDirectoryResource listFiles implementation was faulty. Should be fixed now.
I had to update the test to expect some "phantom" directory entries when dealing with jars. However, that's behavior that is identical to as if the jar were extracted. For example, if jar contained file "foo/bar.txt" the Dir["...jar!*/"] now correctly returns both .jar!/foo and .jar!/foo/bar.txt entries, since if extracted, foo/ directory would be created.
This should fix #1453 for real now.
This also includes "phantom" jar directory entries, even if a zipfile directory entry does not exist.