Issue with ROM and JRuby, auto_registration of relations fail with an empty klass_name in lib/ruby/gems/shared/gems/rom-2.0.2/lib/rom/setup/auto_registration.rb.
To repro:
$ bin/console
> LibraryApiClient.setup do |config|
config.api_url = 'https://example.com'
config.token = 'SOME TOKEN'
end