JPMS module-path and layers

[Alex Orlov]

Hi all,
 
I want to understand all details of module-path and layers in java9+ and I have two questions:
*  As I understand modules on module-path are added automatically only to boot layer and not added automatically to any other layers. I mean, if any child layers are created module-path will be ignored for them. Is this correct?
*  Not all modules from module-path are added to boot layer, but only main module and dependent modules. For example, if we have  A ,  B ,  C ,  D modules on module-path and  A is main module and uses  B ,  B uses  C , then  D module won't be added to boot layer. Is this correct?
Could anyone help me with these questions?
 
--
Alex Orlov