The fact that you are required to export package names from modules has an interesting implication on the way we organize our types into packages in Java 9. Historically, the package construct has been used by Java developers to provide namespaces for Java types. While these namespaces created by package names serve the purpose, at least in theory, to prevent type name collisions and to affect visibility of package-private member variables and types, they also serve a slightly more informal purpose of grouping related types for search-ability and maintainability of code.
There's an additional significance to packages in Java 9 that affects how you group your classes and other types into packages--visibility outside modules. For instance, if you need to hide type A within a module and export type B to outside the module, you are essentially required...