JPAContainer refresh issue

I use JPAContainer 2.0 to access MySQL. I have related entities. Let's say Person & Address
I try to use nestedProperty functionality in JPAContainer to display Person table. 
like:         personContainer.addNestedContainerProperty("address.street");

I use separate JPAContainer for Address entities. Sometimes I need to change address. How to update new changed address in Person container? Is there an elegant way to do it?

Also I found that JPAContainer has itemRegistry with a lot of weakReference<> objects. When I try to refresh an item by id (e.g. call container.refreshItem(id) ) I see a lot of identical SQL queries for every weakReference. Is there a way to get rid of this?