creating a simple rule engine in java

Question

I am exploring different ways to create a simple business rule engine in Java. I need to present the client with a simple webapp that lets him configure a bunch of rules. A

Answer 1

Implementing a rule engine is not trivial. A meaningful rule based system has an inference engine that supports both forward chaining and backward chaining, as well as breadth first and depth first search strategies. Easy Rules has none of this, it just executes all rules once and only once. Drools supports forward- and backward chaining, and afaik also supports depth first and breadth first. It's explained here.

From my experience, Drools is the only meaningful Rule Engine for java. It does have its limitations. I must say, I have used Drools 5+ years ago.