Jess is a fast, light rule engine and scripting environment written entirely in Java. You can build Java software that has the capacity to "reason" using knowledge you supply in the form of declarative rules. It is supplied as a programmer's library, making it ideal for embedding in larger applications. Jess includes development tools built on the Eclipse platform. It is free for academic use and can be licensed for commercial use.
This release adds support for the "allowed-values" slot qualifier, with static and optional dynamic checking. It includes a number of bugfixes and many documentation fixes.
URL: Jess, the Rule Engine for Real Programmers