How to set a relative classpath in Gradle

Question

I have a project "A" with 2 packages, "B" and "C".

Whenever I try to read a file in packages "B" and "C", I need to give the full path, from the root of the project "A". When I print the "user.dir" system property, it gives me the root of the project. Do I need to configured a value in my build.gradle(s) so the packages read from the relative classpath? (i.e, instead of "B/src/main/resources/file.yml", it would be "resources/file.yml" or just "file.yml".