Major Description
I've only seen this when entities are defined in an XML mapping file, and then only in some difficult to replicate classloader environments.
The same XML mapping file may be parsed more than one time, resulting in a misleading warning message about duplicate metadata. The metadata is in fact identical, and does not indicate a problem.
To detect this condition we can store the source file and line number where the meta data was defined, and only issue the warning if the metadata is defined in a different location.