Want to read and write Word and Excel files from Java? Opening Microsoft File Formats to Java tells you how. Or at least some of how.

This article tells you how to use Apache POI to read the OLE 2 Compound Document format, which both Word and Excel use, but it doesn't tell you how to read the application specific structures.

Actually, I have always used Python for this kind of work. And since Word & Excel are installed on all the machines that I want to run my utilities on, COM automation (at which Python excels) was the obvious solution. Worked, too.