Full example is attached.
File One.java contains the import for com.Two, and references that imported class in a JavaDoc comment:
* Blah blah blah.
* @see Two
Checkstyle reports an unused import:
It's true, the import isn't required for compilation; however, removal of the import will cause JavaDoc errors:
C:\public\bugs\checkstyle\javadoc_reference\src\com\One.java:9: warning - Tag @see: reference not found: Two
I think the import should not be considered "unused" in this case.