I think I have found another corner case on the https://hibernate.atlassian.net/browse/HHH-9798 regression. The cited example is: @OneToOne(fetch = FetchType.LAZY) @JoinTable( name = "ITEM_SHIPMENT", // Required! joinColumns = @JoinColumn(name = "SHIPMENT_ID"), // Defaults to ID inverseJoinColumns = @JoinColumn(name = "ITEM_ID", // Defaults to AUCTION_ID nullable = false, unique = true) ) protected Item auction; but an equally similar case ought to be: @OneToOne(fetch = FetchType.LAZY) @JoinTable( name = "ITEM_SHIPMENT", // Required! ) protected Item auction; The rationale here is that a @JoinTable is used to “not have the null rows” that would be present if a @JoinColumn was to be used on an @OneToOne(optional=true). I cannot find in the spec where this is implied, required, or excluded. Otherwise one would have to say: @OneToOne(fetch = FetchType.LAZY) @JoinTable( name = "ITEM_SHIPMENT", // Required! inverseJoinColumns = @JoinColumn(nullable = false, unique = true) ) protected Item auction; Thoughts? -Jason