Davisor Offisor
A XML/SAX -compliant 100% pure Java Microsoft Word document content parser, with easy DOM/XSLT integration. Exposes also document structure, style information, and even graphics. [Commercial, demos]
ExcelAccessor Bean Suite
JavaBeans for working with Excel spreadsheets using COM. Requires Microsoft Excel. [Open Source, IBM Public License]
ExtenXLS Java/Excel Toolkit
Dynamic Excel reporting in their Java web applications. [Commercial]
Jackcess
Pure Java library for reading and writing MS Access databases. [Open source, LGPL]
Java Excel API
Class library for read/write and modify Excel 95, 97, 2000 spreadsheets. [Open Source, LGPL]
Outlook PST to Unix mail box converter
Converts .pst mail files to unix mbox files. [GPL]
POI
APIs for manipulating various file formats based upon Microsoft's OLE 2 Compound Document format using pure Java. Most MS Office files use OLE2CDF. [Open Source, BSD-like]
Tonic Systems' Java Powerpoint Library
A pure Java class library for manipulating PowerPoint documents. The library provides a reasonably complete API for working with text, graphics and images within PowerPoint documents. [Commercial]