Christian Beikov, thanks for your fix. II believe it will work when the column in the embeddable is annotated with:

@Column( insertable = false, updatable = false ),

but it doesn't work if the Map is annotated with:

@MapKeyColumn(name = "language", insertable = false, updatable = false)

The code checking for duplication needs to exclude non-insertable, non-updatable columns from the map key as well as the map value.

Currently, SimpleValue does not retain information about insertable or updatable columns. I plan to extend SimpleValue to do that.