Public API clarifications for SHACL, native store and other storage modules

[abrokenjester]

This PR addresses GitHub issue: eclipse-rdf4j/rdf4j#619 .

[hmottestad]

The package-info.java files, are those the java 9 module files?

[abrokenjester]

The package-info.java files, are those the java 9 module files?

No, package-info.java is a much older mechanism, it's purely for providing metadata about packages: package-level javadoc (the first line in javadoc comment is what shows up as the one-line description on the package list in javadoc), as well as package-wide annotations. For example, you can use it to deprecate an entire package in one go (without having to mark each individual class as deprecated).

It is a replacement for package.html basically - it does the same (javadoc) and more (annotations).

See https://www.intertech.com/Blog/whats-package-info-java-for/ .

[abrokenjester]

Build fails because @InternalUseOnly annotation can not be found - this is part of PR eclipse-rdf4j/rdf4j#1492 .

[abrokenjester]

@rdf4j-bot run tests