If an annotation processor reports messages as Kind.NOTE, javac prints them to stderr. You might expect them to go to stdout, as tools generally treat text printed to stderr as potential warnings or errors.

---%<---
$ javac .... > /dev/null
Note: pkg.C to be registered as a java.lang.Runnable
$ javac .... 2> /dev/null
$
---%<---

As a consequence, when running <javac> from 'ant -q', NOTEs from processors are still printed, when you would want only warnings or errors to be printed.