“Is a rule different from an if-statement in Java?” My daughter, a summer intern at my company, asked this question that almost all Java developers do when first introduced to rules. The answer, of course, is that they are vastly different. And those differences reveal the very heart of a rule engine. I explained to her that even though it is common to think of rules as an “if-then” statement, it is more accurate to think of them as “when-then” statements. Whenever the condit