I found this annotation @Where in the documentation, and I was wondering what the details of its operation were.

It seems pretty clear that putting a @Where clause on a collection will filter the entities in the collection when it is loaded from the database. Applying it to an entity class would add a sort of "default" filter that applies to queries and collections for that entity.

But:

If I still have references to "filtered out" objects in other entities, will those references still work?

If I want to look an object up by ID, and it's "filtered out", will it be returned?

If I wanted to write a query which bypassed or ignored the where clause on an entity class, could I?

if you also have a where clause on the ontity itself you can do 1 and 2
But then 3 will not be possible

The Filter feature is more flexible since it can be enabled and disabled

Thanks emmanuel!