Been lurking around for a while to try and find a solution to this problem with no luck. I've been following McJty's tutorial. And while I have big things envisioned, at the moment I'm just testing if I can add a single item into a creative tab. And while I've knocked out all the errors the IDE was throwing at me, trying to run the GradleStart gives me an error from the Client Proxy "Class not found" but the client proxy only points to one class inside of it and that class very much exists.
Mod coding: https://github.com/Sarelm/Dynams/blob/master/Dynams.java