July 9, 2011. Java 7 Launch Celebration. JSR-331 has been presented at JUGChennai in Chennai by Rajmahendra Hedge - see http://www.jugchennai.in/2011/07/09/jugchennai-java-7-launch-celebration-at-chennai

April, 2011. JSR-331 common implementation has been extended with constrained set variables. This is a basic implementation that can work with any underlying CP solver (even if it does not support its own set variables).  Several examples that demonstrate how to use set variables are provided.  You may try the latest JSR-331 by contacting This e-mail address is being protected from spambots. You need JavaScript enabled to view it . 

March, 2011. Google published a new product "or-tools" with a Java-based CP interface. Read more here.

January 10, 2011. JSR-331 has successfully passed the Public Review Vote - see http://jcp.org/en/jsr/results?id=5118.

Sep. 22, 2010. Java Community Process (JCP) announced today at JavaOne Conference in San Francisco that JSR-331 won JCP Award "The Most Innovative JSR of 2010".

Sep. 10, 2010.  A productive CP Standardization Discussion was held at CP-2010 on September 10 in St Andrews, Scotland. The presentation had summarized the current state of the CP Standardization process. The panelists Peter Stucky(G12), Laurent Michel(Comet), Chris Jefferson(Minion), Nicolas Beldiceanu(Choco), Radoslav Szymanek(JaCoP), and Helmut Simonis(4C) responed to questions of the very involved CP-2010 audience and discussed  further standardiziation directions. Along with JSR-331, the discission was around CP Domain Speciffic Language (CP DSL), Common Interchange Format (CP XML), Standard Test Problems, CP integration with commercial products and applications, and more. It became an important milestione on the road to CP standardization.

August 29, 2010. The JSR-331 has been nominated for the most innovative JSR of the year for a Java Community Process Award.

July 30, 2010. A new version of the JSR-331 Specification v.0.6.1 is available for review. Please look at:
- specification document
- javadoc
- changes in v.0.6.1
The SVN repository with two initial implementations and Examples and have been updated too. Thank you everybody to constructive comments and suggestions. 

July 24, 2010. There is a new Blog devoted to CP standardization - www.cpstandard.wordpress.com. Please provide your comments to a just posted standardization roadmap

CP Standardization Discussion will be held at CP-2010 on September 10 in St Andrews, Scotland.  We invite all CP vendors and industrial users of constraint programming to nominate representatives for the Discussion Panel and to make brief presentations about their positions regarding CP Standardization. Please send names of representatives to This e-mail address is being protected from spambots. You need JavaScript enabled to view it before August 30, 2010. All CP practitioners and conference attendees are welcome to participate in this important discussion!

July 20, 2010. After receiving a very constructive feedback from CP vendors and experts, we are working on a new JSR-331 release 0.6.1. Its beta is already available for downloads upon requests. An updated specification document and modified examples on this website will become available soon. Check again in a few days.

June 15, 2010. The problems of CP standardization and integration with LP/MIP tools have been discussed at CPAIOR-2010 workshop "Open Source Tools for Constraint Programming and Mathematical Programming" - see the JSR-331 presentation

May 1, 2010. Noel Lynch ( This e-mail address is being protected from spambots. You need JavaScript enabled to view it ) has successfully integrated an initial JSR-331 implementation with Scala (see example).  

April 9, 2010. The JSR-331 Early Draft documents have been published at http://jcp.org/en/jsr/detail?id=331. Any CP vendor who wants to create a JSR-331 implementation could receive a secure access to the proper SVN repository.  The first 3 open source implementations are already on the way: 
1) Choco - http://www.emn.fr/z-info/choco-solver/index.html
2) Constrainer - http://sourceforge.net/projects/constrainer
3) JaCoP - http://jacop.osolpro.com/

March 17, 2010. The JSR# 331 Early Draft is now available for public review. See the  Specification Document v.05.1

March 15, 2010. The section "Problem Resolution" now includes a proposed list of standard Variable and Value Selectors.

Feb 04, 2010. The JSR# 331 Early Draft is scheduled to be released in March 2010. All CP experts are invited to join JSR-331 Expert Group from http://jcp.org/en/jsr/summary?id=331 and contribute (you may become a member or an observer).  The proposed architecture suggests that all JSR-331 implementations will share the same names for packages and major classes and methods. It will allow a business application developer to easily switch between different implementations without any (!) changes in the application code. Users will be able to write their constraint-based engines once using only common CP API and use different CP solvers by changing implementation specific jar-files in their classpath. Please provide your comments and suggestions.

Dec 19, 2009. Based on recent conversations with different CP experts the previously published CP API for Java has been essentially simplified. Two main interfaces Problem and Solver follow a minimalistic approach with a clear separation of problem definition and problem resolution concepts. The new date for the Early Draft Review for the JSR# 331 is March 1, 2010. Along with a pure interface it will include implementations for common concepts and will specify a structure for reference implementations.

Nov 1, 2009. Peter Stuckey made a valuable contribution at the Discusion Forum. This is the first attempt at this forum to standardize the most popular global constraint "alldifferent".  Thank you, Peter! Comments from other experts are very welcome.

Oct 21, 2009. Javadoc for CP API for Java has been updated. As suggested on the discussion forum by many people, we removed the most of synonyms, so the interfaces such as Var and VarReal are much more compact now. We've cleaned-up the main interface CSP by removing some duplication (not completely yet). We assume that standardized global constraints will be placed in the package  "java.constraints.global" utilizing the Global Constraint Catalog but we understand that this process will take time. Meanwhile, the interface CSP includes only the most popular forms of such constraints as "allDiffirent", "elementAt", "cardinality" and "globalCardinality", "sum", "scalarProduct" presented in a way intuitive for a Java developer (not a CP expert). This API will be extended as more global constraints will be standardized and placed into the library "java.constraints.global".

Sep. 23, 2009. There was a special Standardization Discussion Session during the CP-2009 in Lisbon, Portugal. The panellists included: Jacob Feldman, Narendra Jussien, Peter Stuckey, Petr Vilim, and Christian Schulte. With an active support from the audience and multiple informal disscussions between experts, this event became a positive milestone on the road to the CP standardization.  See the presentation.

Sep 18, 2009. Javadoc for CP API for Java has been updated. The name of the main package has been changed to "java.constraints". A new interface "SolutionIterator" has been added.

August 31, 2009. We've switched to a more sophisticated Discussion Forum. 

August 18, 2009. A new Java Specification Request JSR# 331 has been approved by the JCP Executive Committee. All CP experts and  application developers interested in CP are welcome to contribute as a member of the JSR Expert Group or as an observer.

July 30, 2009.  CP API for Java has been updated by adding interfaces for constrained Real Variables - see VarReal, aditional tracing and logging facilities. 

June 23, 2009.  CP API for Java has been updated by adding interfaces for constrained Set Variables - see VarSet. There is also a new example "Manners" that demonstrates the use of set variables.

May 30-31, 2009. CP standardization approaches have been informally discussed during CP-AI-OR 2009

May 2, 2009. The first version of www.cpstandards.org has been published and announced at the ACP News.

Check the Discussion Forum