CS2J has two components:

- CSharpTranslator:
     This builds the cs2j.exe executable.  This executable runs
     directly under Windows and under Mono on other platforms
     (http://www.mono-project.com/Main_Page).

     This work is licensed under the MIT / X Window System License
     (http://opensource.org/licenses/mit-license.php). 

     With this licensing then the produced Java code should be
     completely unencumbered and you can do what you want with it.

- CS2JLibrary: 

     This contains the XML translation files that direct CS2J to
     translate .Net framework calls into appropriate Java code, and
     the CS2JLibrary Java support library that translated applications
     include.

     This work is licensed under the Apache License, Version 2.0
     (http://www.apache.org/licenses/LICENSE-2.0).