Nick, I agree with what Steve is saying, minus the omitted != empty value part. Like he said, the fact that the setting is a negation would throw me off. If I wrote an app, omitting <exclude...>, listing no classes, I'd be surprised if they weren't picked up in scanning. Again, that's all entirely within a Java SE context.

For now, I'll go back to the following for all JPA versions:

1. Omitted == do scan
2. <exclude-unlisted-classes /> == don't scan.
3. <exclude-unlisted-classes>false</exclude-unlisted-classes> == do scan.
4. <exclude-unlisted-classes>true</exclude-unlisted-classes> == don't scan.