I use lein uberjar to create a standalone jar of an application.
When executing
java -jar dataloader-0.1.0-SNAPSHOT-standalone.jar,
If you want to read the content of the configuration.json file, do not call io/file. Instead, use slurp function, like that:
configuration.json
io/file
slurp
(def config (slurp (io/resource "configuration.json")))