In October 2008, Vaclav Pech started a pet open-source project called GParallelizer with the intention to build several easy-to-use Groovy-based DSLs. These were built around the Fork/Join and the ParallelArray concept implemented as part of jsr-166y java concurrency library. A thin abstraction layer that allowed Groovy closures to run asynchronously was also included.

From the impressions of Scala, the actors abstraction was added shortly after and has gradually evolved from a mere experiment into a usable implementation.

Some time later, inspired by Jonas Boner’s experiments with dataflow concurrency, the concept of dataflow variables, streams and tasks has been included as well as the Clojure’s agent concept has been implemented.


In September 2009, Dierk Koenig, Alex Tkachman, Russel Winder and Paul King joined the team, when the project moved to Codehaus under a new name — GPars.

In October 2009, the dataflow abstraction had been enhanced with dataflow operators and an initial Fork/Join convenience layer.

Since December 2009, GPars has had a logo.

The team made their first release under the new project name in December 2009 when GPars 0.9 came out with a fancy User Guide.

From the increasing amount of feedback and comments, it become evident that GPars had gained some attention.

GPars was presented at several conferences in Europe and North America (e.g. W-JAX 2009, JAX 2010, Jfokus 2010, GeeCON 2010). You may also check out a more complete list of Presentations and Events.

Jon Kerridge from the University of Kent joined GPars and contributed his JCSP wrapper library, called Groovy CSP, to the project code base.


GPars reached another milestones in May 2010 with the 0.10 release, 0.11 in October 2011, 0.12 in May 2011 and 1.0 in December 2012.


The most recent release, 1.2.0 arrived in July 2014.