Zilonis provides a Multithreaded Rules Engine platform and a scripting environment for Java based applications. The core of the Zilonis platform is based on a variation of the forward chainning Rete algorithm described in "Rete: A Fast Algorithm for the Many Pattern/ Many Object Pattern Match Problem", Charles L. Forgy, Artificial Intelligence 19(1982), 17-37.). The implementations follows the optimizations and the structure used in the Soar system, and the ones well described in the paper: "Production Matching for Large Learning Systems", Robert B. Doorenbos. 1995 Multithreaded Capabilities A nice feature and contribution from Zilonis, is that it is multithreaded. Because of that, it is easy to reuse a set of rules across several concurrent users in a safe way, without creating copies of the rules and the engine, as you would have to do if you were to use other engines.
The Java Concurrency API and Deadlock Prevention in a RETE Rules Engine to Implement a Pricing Service (2007)
Production Matching for Large Learning Systems