Mapping between the mimetype and file extension is being done. Mimetypes (http://svn.apache.org/repos/asf/tika/trunk/tika-core/src/main/resources/org/apache/tika/mime/tika-mimetypes.xml)
It would be an improvement to get the file extension from the detected mime type. Example detected "audio/mpeg", file extension "mp3"
In short, make url pattern/ file extension public
(when working with blobs)