Review jOOQ's reflection usage for JDK 9 / Jigsaw compatibility

[lukaseder]

There are two kinds of reflection usage in jOOQ:

1. The one employed in DefaultRecordMapper. Here, the Javadoc should document jOOQ's expectations towards third party modules, which might expose POJOs that need to be "opened" by the module definition, for reflection to work
2. The one employed in jOOQ's internals to avoid explicit dependencies on JDBC drivers, e.g. ojdbc's Connection.createARRAY() calls. These should work with JDK 9 as well, as they only use public API, but you never know.

This issue should check for JDK 9 compatibility and document any caveats.

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See also:

• http://www.jasondl.ee/posts/2017/compiling-for-java-8-and-java-9.html
• https://blog.codefx.org/java/java-9-migration-guide/#Dependencies-On-Java-EE-Modules
• https://twitter.com/nipafx/status/892671320990679041

[lukaseder]

No major issues found as internals are not using any reflection magic if not needed.