Is it possible to add JRE and JDK modules in child layers?

[Alan Bateman]

On 18/01/2024 13:49, PavelTurk wrote:
> :
>
> Do I understand it correctly that it is ABSOLUTELY, ABSOLUTELY 
> impossible to do find a solution for this problem?
> I mean that all today's knowledge in software development are still 
> not enough to find a way
> a) to provide integrity of the platform and b) to load standard 
> (JRE/JDK) modules in child layers?

I didn't say it was impossible, instead I listed down some of the 
challenges with finding a workable solution to this type of use case. 
The science isn't too difficult, it's mostly about slicing a module 
graph and reifying the slices as a stack of ModuleLayers so that the 
ModuleLayer.Controller handed out to the container is for a ModueLayer 
that doesn't include the modules mapped to the boot or platform class 
loaders. The harder part is coming up with an API that looks like it has 
always been there.

For now, deploying the container with --add-modules ALL-DEFAULT is not 
terrible. It ensures that all modules in the run-time image that export 
an API are in the boot layer so there shouldn't be any issues with 
modules in child layers requiring modules that the container doesn't 
transitively require.

-Alan