Rejected issue covers this partially. I might have misunderstood, but it seems the reason for rejecting is that @NotFound provides the same capability.
All information I could find for JPA and other ORM tools indicates that this capability is supplied by @OneToOne(optional=true). Hibernate seems to be the lone ORM tool that requires the use of a proprietary annotation: @NotFound.
@NotFound works, but the problem is that it makes the application no longer be pure-JPA. Not supporting pure-JPA outer joins would seem to be a major bug.
Hibernate 3.3.1, annotations 3.4.0, MsSQL DB.
I've confirmed that optional=true works as expected when the associated entities do not share the same ID.
This will have to wait until we have a response about how @NotFound functionality relates to the spec with respect to an optional one-to-one on a primary key.
optional=true was broken by the fix for HHH-5109.
For now, I'll back out of the fix for HHH-5109. A new fix for that does not break optional=true will be covered by HHH-6723.
Backed out of in master and 3.6.
Bulk closing tickets resolved in released versions