Is there any reason why this option is not the default? I find that the more I want to make my domain objects responsible for business rules and validation, the more I turn this option on to make sure this code does not get executed when hibernates needs to get and set values. What is the trade off for setting this option on all the time?

We use access="field" as our default for exactly the same reason - we don't want developers business logic in the getters and setters being triggered during persistence.

I guess the drawback would be the extensive use of Reflection (and/or CGLIB, or however Hibernate accesses the private attributes?) to access the private attributes every time a persistence object is retrieved/stored?

Kevin Hooke

But doesn't Hibernate use reflection to call the get/set methods as well? I guess I'm curious what the difference is, if any.

Nope, reflection is only used for direct field access.

And no, I don't think there is realistically any performence difference on a modern JVM.

Another difference is that the code in your mapped objects will have to account for the fact that fields get set by code outside of the class. This means that an instance can be in a state that cannot be produced by the constructors and setters. This can make for some pretty strange bugs.

I've used ORMs that do both, and I prefer Hibernate's default behavior. I also prefer to put validation logic in business session objects. In the end, it's just a more maintenance friendly design, IMHO.