Hi there,
From JPA spec (
http://download.oracle.com/javaee/6/api/javax/persistence/Embedded.html)
"Specifies a persistent field or property of an entity whose value is an instance of an embeddable class. The embeddable class must be annotated as
Embeddable. "
For me it means
you should use it for single attributes, not collections. Howewer, the annotation api doesnt deny it, and with eclipselink, and hibernate it works for me.
but in the xml api, which is better-defined, its not allowed.
So I think you should not use it,
the generic type, or the
targetClass attribute of
@ElementCollection is enough.