I wish did fix the issue. Yes, you can create as many artifacts as needed, in the Artifact settings you can configure which files to package and where, so it's possible to use files from different locations.
Reordering the deployment artifacts in Glassfish App Server in IntelliJ IDEA
this one helps. Yes. Its happening because of the path is wrong. Try to open the jar file using winrar or something like that. Then try to locate your file where you try pass inside getResource. Then try putting that path where inside jar and check running the jar again after compiling