We don't want special rules that distinguish between Java and Luan modules. So I think of this as "User_Utils" subclassing "User". Let's change the names "User_Utils" to "User" and "User" to "Java_User" so that now "User" subclasses "Java_User". The implementation of this is:
require "Java_User"
User = Java_User
Package.loaded.User = User
We can change the "module" command to take a second parameter to do this.
module("User","Java_User")