I posted a little while back about running docx4j on the android platform, and using the DocxToHTML example as a guide. In the more recent version (3.0.1), it says that it can run on the android platform ("Do all this on Android (v3 or 4)").
I was unable to find answers in the updated Getting Started guide to get it running on the android platform, as well as using the Android branch of docx4j at ...