This seems to be a easiest solution, if you know xml processing.
http://www.javaworld.com/javaworld/jw-07-2004/jw-0712-officeml.html
For testing, save this code as a .doc file and...
<?xml version="1.0"?>
<?mso-application progid="Word.Document"?>
<w:wordDocument xmlns:w="http://schemas.microsoft.com/office/word/2003/wordml">
<w:body>
<w:p>
<w:r>
<w:t>Hello JavaWorld.</w:t>
<w:br/>
<w:t>This is a great reporting tool.</w:t>
</w:r>
</w:p>
</w:body>
</w:wordDocument>