[wildfly-dev] About API and leakage

[David M. Lloyd]

Guys, when developing an API that is going to be shipped either as part 
of WildFly as a module or for end-user consumption, I want you to 
remember something:

Every public and protected member of that module *IS* API.  That means 
you can't ever change it without considering compatibility.  "Well I 
just made it public because this other module needs access to it" is not 
a valid excuse, nor is "Well I needed access from another package". 
Both are synonyms for "I screwed up my design at an early stage and now 
I want to break the rules to fix my mistake".

The only exception is if you're developing a component specifically and 
exclusively for use in the modular environment, and you put all non-API 
public members into a specific package or package set which is then 
excluded from export in the module.xml descriptor in the shipped 
environment.

If you do not fall into this exception then you are volunteering to 
personally maintain these non-public public classes for the next 10 
years come hell or high water, because people are surely going to use 
them, and I sure don't want to be the one to maintain them.

-- 
- DML