module-info.java just causes problems

[Alan Bateman]

On 11/05/2016 15:14, David M. Lloyd wrote:
>
> We package several hundred JARs in our modular environment today, only 
> some of which originate in-house.  The dependency information for 
> these modules is established not by the author of these JARs, but by 
> us.  The Maven artifact for such a JAR might stipulate certain things, 
> like Log4j or a certain version of ASM.  When we distribute that JAR 
> though, we don't package the exact artifacts and versions of the 
> dependencies that were stipulated in the Maven POM; instead we package 
> single consistent versions which are ABI-compatible with all of its 
> dependents, or maybe even a completely different artifact that meets 
> the same ABI but performs its functions in a different manner.
>
> Over time the environment we distribute evolves, and we split or join 
> modules, or we rename old modules to introduce a new major version of 
> the same module in parallel, or we replace one implementation with 
> another.  When we do this we may chose to deprecate or eliminate a 
> module from our environment.  Thus we update all the module 
> descriptors that reference the deprecated module, and set new 
> dependencies on them, and after a certain amount of time, we delete 
> the old module name.
>
> None of the artifacts that we package are impacted by this process, 
> and generally no recompilation is necessary: after all, many of these 
> artifacts come directly from Maven or are otherwise built 
> independently at an earlier time outside of the context of our target 
> environment. It's the ABI that matters; as long as that doesn't change 
> (in an incompatible way), recompilation should never be necessary.  I 
> think "recompile just to be safe" puts us squarely into "turn it off 
> and on again" territory, logically speaking.
>
Thanks for the context. So I'm curious what will happen when you 
download JAR that is a modular JAR where the author have put in the 
effort to declare their dependences and exports, maybe services too. Are 
you going to override that too?

-Alan