The Unnamed Module
All packages that are not in a named module are placed in "the unnamed module."
This includes all the code you have written thus far and all code written without
a module-info.java
alongside it.
This is generally okay. Modules as an organizational tool are most useful for sharing code across "maintenance boundaries." Explicitly
The unnamed module is special in that code within it requires
every other module
and therefore can see every exported package and every class within.