Should the id field of a JPA entity be considered in equals and hashCode?

Question

I hit a problem when writing tests for a database application using JPA2 and EclipseLink:

I add some entity to a database, retrieve it later and want to compare it to an

Answer 1

From the book Hibernate in Action, its recommended to defined a business key and test equality on that. A business key is "a property, or some combination of properties, that is unique for each instance with the same database identity." In other areas it says to not use the id as one of those properties, and don't use values in collections.