Oradocletplus is a project mainly written in ..., it's free.
OraDocletPlus is an enhanced version of the OraDoclet database documentation generator available at http://oradoclet.sourceforge.net/
The tool will automatically generate a set of HTML documents based on the Oracle database schema that you connect it to. It will pull our pretty much all meta-data about the schema, including indexes, column comments, foreign keys, and PL/SQL source code.
I threw these changes together as I needed to generate some database schema documentation quickly and found the original OraDoclet to be a pretty good solution, although it had a couple of bugs, looked very out of date and hasn’t been updated in quite a while.
Note that the original author of OraDoclet was Vladimir Katchourovski – kudos to him for creating a concise & simple tool.
java -jar oradocletplus.jar username/password@hostname:port:sid <output_directory> [<copyright_notice>]
for example -
java -jar oradocletplus.jar fred/password@localhost:1521:mydb c:/temp/oradocs "My Company Inc."