Field with @CreationTimestamp annotation is null while save on repository : <p>(1) Why is the "@CreationTimestamp" field updated to null for a "save" called on the repository with a null value for that field?
I expect that a field annotated with "@CreationTimestamp" is never updated and maintained only once at the time of creation. But it does not work that way in my current project.</p>

<p>(2) I had to include @Column(updatable =false) (in addition to @CreationTimestamp annotation). Why is this necessary?</p>
