@Dennis iirc Java on TIO doesn't know about libraries anyway, and you have to manually give compiler flags specifying their path. That would still work for Java 10.
@Dennis I think you can set the CLASSPATH environment variable
@Marco I didn't use the install script btw. While I could have edited to match the desired location, I'd have to do so every time I update the language. I'm currently simply copying prelude.eg and the two .ego files in the sandbox's home directory, which also makes them discoverable.