I am working on a medium-size Java application with a test harness consisting of 180 tests grouped in 6 packages. Most of the automated tests read one or more input files and create multiple output files which are compared with “control” files. This approach provides an easy way to add more tests without coding. Over a period of three years this lead to the creation of around 350 input files and 600 control files taking 167MB. But as tests change, not all the test data is used anymore, which raise the question is: How can I find the test data files that are still used in my regression testing suite? The search for an answer lead to exploring Java 7, Spring AOP and Aspect J.