How can you edit a word document with Java?
You can use COM to do that also. Use a Java COM interop library like JACOB (JAVA COM BRIDGE): http://sourceforge.net/projects/jacob-project/
Here is a tutorial using Jacob to talk to MS Word: http://www.land-of-kain.de/docs/jacob/
The other library that looks promising and that will solve the cross-platform problem is J-Interop: http://www.j-interop.org/.