Jigsaw and containers

[Daniel Latrémolière]

I have a problem to understand new layout of files in JRE/JDK images for 
the containers use-cases.

Containers (Docker, Flatpak) have a notion of single inheritance, where 
an union FS merge the images of the container with parent containers. 
This give much smaller images of containers when most of the files are 
untouched and inherited from a common parent container.

The layout of JRE/JDK images, with one big file "/lib/modules" taking 
most of the size, seems to be completely anti-modular and particularly 
bad for fast redeployment. Isn't it more modular and space-efficient to 
have not a file "/lib/modules" but a directory "/lib/modules/" where all 
available files, like "0", "1", etc. would be loaded.

By example, an application suite can have a parent container with the 
Java standard library and common libraries of the application suite 
(creating a file "lib/modules/0" with the set of common modules). Each 
application would be a container inheriting common code from parent and 
with a file "lib/modules/1" with the own set of modules for the application.

Daniel.