Here's what I did: I put my name and my ids, version of the JDK used and host platform (OS). Just it.
OpenJDK Runtime Environment (IcedTea6 1.9.9) (6b20-1.9.9-0ubuntu1~10.10.2)
OpenJDK 64-Bit Server VM (build 19.0-b09, mixed mode)
Well, just be aware of the following:
You may develop your code using any implementation of the Java 2 platform, but the submission that you return must have been tested and shown to work under a production (not development) version of the Sun Microsystems' Java 2 platform and that platform must not have been superseded by a new production version for more than 18 months by the time you make your submission.
I don't know if they can see the "OpenJDK" as a problem... I'd put a production version of the JDK (something like 1.6.0_27 or 1.7.0).