For the upcoming 0.12 release gpars now provides a Pdf version of the user guide. Check it out at http://gpars.org/SNAPSHOT/guide/gpars-guide-0.12-beta-1.pdf
Great thanks to the CZJUG hackathon team in Prague, who did the implementation, as well as to Andres Almiray of the Griffon project, who shared his valuable insight into the matter.
In short - GPars is now using the Java 7 concurrency artifacts. Russel Winder has taken initiative and with an official blessing from the jsr-166 team he mirrored the most recent jsr-166 artifacts into the maven repository. This allowed us to remove the dependency on the ancient coconut clone of the fork/join framework and use the "real" live matter. With all the improvements and fixes that jsr-166y has gone through during the last couple of years this has immediate effect on GPars plus once Java 7 ships with jsr-166y bundled, we will be ready.
Nothing changes on the user side of things, provided you're using an automated dependency management tool such as Gradle or Maven. The recent 0.12-beta-1 snapshot correctly declares the new dependencies. You may check out more details in the snapshot user guide.
Enjoy concurrency in Groovy!
Yours GPars Team