I had a little chat with the guys at the findbugs mailing list which has made this all a lot easier, even to thickheads like me:
It turns out we do not have to "subscribe" to anything like JSR-305 at all. I probably watched the movie "Highlander" too much in my teens, which had me searching too much for the "there can be only one" kind of solution. Since I love source code, I'll just point you all at the findbugs source I was given: http://code.google.com/p/findbugs/source/browse/trunk/findbugs/src/java/edu/umd/cs/findbugs/ba/NullnessAnnotation.java#55 This shows the part where findbugs searches for /any/ kind of @Nonnull annotation and also @Nullable. The guys at findbugs realized that there does not have to be only one. And it turns out the IntelliJ guys also understood this, so we can add any arbitrary annotation to the "nullability" section of the idea code-style file. (As for eclipse, well - ahem - I'm sure the eclipse users out there will solve this. It' s OSS :) So the proposal is really simple: We make "maven-annotations" under maven-shared. RC for this can be found at https://github.com/krosenvold/maven-annotations.git this implementation does /not/ depend on any specific "jsr" or any other dependency, so we can freely leak this from maven core into plugins. We specifically leak org.apache.maven.shared.annotations.Nonnull org.apache.maven.shared.annotations.Nullable from maven core into plugins. From the moment we publish these, they cannot ever change. If core exposes version "1.0" of "maven-annotations" and a plugin includes version "1.1" of maven-annotations, the *additional* definitions in 1.1 will be loaded from the 1.1 jar, while Nonnull and Nullable will leak in their 1.0 versions from core. Kristian
