I raised a MP Config Spec issue [1] and discussion. Based on how Payara is doing it, I believe that Geronimo Config checking for empty strings is incorrect. GConfig throws NoSuchElementException if the value is empty, but it seems like this is expected behavior and should instead return empty strings.
John [1]: https://github.com/eclipse/microprofile-config/issues/216 [2]: https://groups.google.com/forum/#!topic/microprofile/k5fcWItjvsY
