Sorry for the very late reply, I don't follow this forum. If you have any questions for us at Oracle, you may want to flag Andy (who works for Oracle, but not in the Java group).
> is the mindstorms EV3 version a special jre-version? I thought it is the standard ARM v5 version, isn't it?
Standard ARMv5 version so far. We created a special download page so that we had a place to put Lego-specific links & information. We may in the future host other Lego-related downloads or links, or (if necessary) a special JRE build. We *did* run through the effort of validating the binary on actual EV3 hardware prior to posting it. Thanks to Lego for the hardware, and to Andy for help getting the QA environment set up!
> About the licence: Is it legal to use a leJOS mindstorms in challenges or may this harm any copyrights?
The license you accept when you download the binary answers this question. It says:
"We grant you a nonexclusive, nontransferable limited license to use the programs only for the purpose of developing, testing, prototyping and demonstrating your application"
A robot building challenge should fall under "demonstrating your application" so no worries. Besides, it would be kind of silly of us to make a Java binary available to the LeJOS community under terms that prevented the community for using it. Believe it or not, we actually think about things like this
Vice President, Product Management
Java & Internet of Things