if i understand it correctly your suggestion implies that if i want to have 1 public class and 9 package protected that do the actual job in java, i have to create a separate project declare those 9 as internal and then have this project compiled and accessible using Maven or Gradle or whatever one uses for the DI?
Imho that’s an overkill…
Note that if i do 10 classes in one file 9 private i wont even be able to test those 9.
I personally never saw any code working around package protected access using same package name… it will just differ from your regular package structure and will constantly remind devs “fix me this is a shitcode”.