Moving to intellij i'm trying to understand properly the logic behind the its project structure. I come from eclipse. After reading for a while i understood the relation between workspace and project, then between project and modules. However something that is puzzling me is the logic of the default project configuration in Intellij. Indeed, when you create a project there is an initial module which to a certain extend is equivalent to the Project itself. To be more precise, the initial module folder is the Project folder. This is kind of confusing to me. Then when you add more module they are sub-module of that module.
My first question is what is the rationale of making this first module equivalent to the project folder ?
Following this, i would further ask, what the point of having modules as sub-module of others. In eclipse i use to have simply different project (i.e. module) independent from each other and adding the dependency as necessary. So how does the Idea solution makes it better, if not what is the rational here ?
I saw that one can start an empty project and then add modules to it. However in that case, the modules added are added as subfolder of the Project and therefore there is no initial module equivalent to the Project folder ? So why this difference and what is the rationale behind it ?
What would be the better approach, the first or second ?
Would it be ok to have this first initial module with no src or test folder but just with the proper facet so as to spread it to the sub-module?
I would appreciate if someone could explain a bit the rational of all of it ?
I will move to SBT soon (i.e. maven structure which I suppose inspired all modern IDE project Structure) if one want to explain within that context fine, nevertheless i want to understand the rationale in intelliJ first.
PS: What i'm looking for is some advise for some multi-module project structure in Intellij as i'm moving my eclipse workspaces to it.