Jikes RVM Project web pages ( http://www.jikesrvm.org ), code is at https://github.com/JikesRVM/JikesRVM.git
If you have made some changes to the web site and want them applied, send your patches to the jikesrvm-core mailing list or open a pull request.
If you want to contribute code to the Jikes RVM, please take a look at our contributions page