jWordConvert is a Java library which can read and render Word documents natively to convert to PDF, to convert to images, or to print the documents automatically. The library is 100% Java, so it can run on any platform which supports Java. It does not use any third party software or native calls, and can be run in a server environment or integrated into a desktop application.
FF Multi Converter is a simple graphical application which converts audio, video, image, and document files between all popular formats, using and combining other programs. It uses ffmpeg for audio/video files, unoconv for document files, and the PythonMagick library for image file conversions.