posted 15 years ago
OpenOffice -which can be run as a GUI-less server, and has a Java API to access it that way- should be able to import and append RTF files.
I'm not aware of a Java library for handling RTFs, though. But RTF has a pretty simple syntax. It's not hard to write a parser for it, and for a limited subset or RTF -if you can make such an assumption- it may be feasible to append two files by text manipulation.