Where is the business logic?

One of the challenges in maintaining legacy systems is to be able to locate business logic in the code, and isolate it for different purposes, including implementing requested changes, refactoring, eliminating duplication, unit testing, and extracting business logic into a rule engine. Our new idea is an iterative method to identify the business logic in the code and visualize this information to gain better understanding of the logic distribution in the code, as well as developing a domain-specific business vocabulary. This new method combines and extends several existing technologies, including search, aggregation, and visualization. We evaluated the visualization method on a large-scale application and found that it yields useful results, provided an appropriate vocabulary is available.