Open Source Rule Engines in Java

Open-source BRMS that treats Excel tables as executable rules. Business users author and test rules in spreadsheets; deploy as REST APIs with type-safe validation and WebStudio UI.

Business rule management system and rule engine for the JVM with forward- and backward-chaining inference. Includes a DMN engine and complex event processing (CEP). Part of Apache KIE.

Decision-table-based rules engine with rules defined in Excel and conditions/actions in a domain-specific language (EL). Deterministic execution order; Java and Go implementations, used in production for eligibility and business logic.

Rule-based JVM language combining Prolog-style rules with Java. Extends Mandarax with derivation and reaction rules, agent messaging (JMS, JADE), and transparent access to DBs, XML, and web services.

Decision intelligence platform combining business rules, ML, and optimization. Create and manage rules in Excel or Google Sheets; deploy as decision services (REST, serverless, containers).

Java rule engine for term rewriting; implements term systems with rules and actions. Used for DSLs, computer algebra, formal model analysis, and software engineering. JSR-94 support.

Forward-chaining rule engine for Java. Intended for embedding in application servers, client applications, and servlets to drive business logic by rules.

JSR-94-compliant rule engine for Java, built on ABL (Armed Bear Lisp) and Lisa. Supports CLIPS-like rules, decision trees, and expert systems with Java objects.

JSR-94 1. 1 compliant forward-chaining rule engine. Rules are loaded from XML or via API (e.

Pure Java rule engine with backward chaining. Supports multiple fact and rule types (reflection, databases, EJB), XML (RuleML 0. 8), and J2EE-compliant inference.

Business rules and process management tool with a rules metadata repository, rules engine, and web-based UI for authoring and testing rules, plus process orchestration.

Lightweight Java rule engine (non-JSR-94). Rules are Java classes implementing a single passes method; chain them in XML to build composite rules.

Integrated tools for semantic web rules and ontologies (RuleML, SWRL, OWL). Supports Situated Courteous Logic Programs, semantics-preserving translation between rule languages, backward/forward inferencing, and WSDL procedural attachments.

Multithreaded forward-chaining rules engine for Java, based on a Rete variant (Forgy/Doorenbos style). Enables safe reuse of rule sets across concurrent users without copying the engine.

JSR-94-compliant rules engine where rules are written in Java. Uses the Java type system and naming conventions to plug rules into the inference engine without a separate rules language.

Mandarax Compiler: a scripting language for derivation rules and a compiler that generates executable Java code. API similar to Mandarax but compiles to Java rather than using an interpreter; server-pages-style deployment.