What are ways to keep hashCode/equals consistent with the business definition of the class?

Question

Object javadocs and Josh Bloch tell us a great deal about how hashCode/equals should be implemented, and good IDEs will handle fields of various types correctly. Some discussio

Answer 1

How about you write unittests for each class you want to protect. The unit tests should

1. Use reflection to count the number of fields, and compare with locally stored field names (and types).
2. If a change in number of fields (or type of fields) has been detected, then invoke hashcode. If the value is the same, then fail the test case. Alert the developer that fields of a class have been changed, and that the developer should : Update the equals and Hashcose, and update the unittest.
3. Make sure the unittest runs in a nightly build.