public class Product extends GenericEntity {
    @OneToMany(fetch=FetchType.EAGER, mappedBy = "product", targetEntity = ProductPrice.class, cascade = {CascadeType.ALL}, orphanRemoval=true)
    @Fetch(FetchMode.SUBSELECT)   
    @Cache(usage = CacheConcurrencyStrategy.READ_WRITE, region="ncStandardElements")
    private List<ProductPrice> productPrices = new ArrayList<ProductPrice>();

    @OneToMany(fetch=FetchType.EAGER, mappedBy = "product", targetEntity = ProductPrice.class)
    @Fetch(FetchMode.SUBSELECT)   
    @MapKeyJoinColumn(name="CURRENCY_ID")
    @Cache(usage = CacheConcurrencyStrategy.NONSTRICT_READ_WRITE, region="ncStandardElements")
    private Map<Currency, ProductPrice> productPriceMap = new HashMap<Currency, ProductPrice>();
}

public class ProductPrice extends GenericEntitySimple {

    @ManyToOne(targetEntity = Product.class, optional=false)
    @JoinColumn(name = "PRODUCT_ID", referencedColumnName = "ID")
    private Product product;
}

public void removeProductPrice(ProductPrice price){
    Product p = price.getProduct();
    //Map<Currency, ProductPrice> productPriceMap = p.getProductPriceMap();
    //productPriceMap.remove(price);

    List<ProductPrice> prices = p.getProductPrices();
    prices.remove(price);
    p.setProductPrices(prices);
    productDao.merge(p);
}

Jun 17, 2013 3:45:29 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet appServlet threw exception
org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: com.netasoft.commerce.framework.catalog.model.ProductAttrValueExt
   at org.hibernate.engine.ForeignKeys.getEntityIdentifierIfNotUnsaved(ForeignKeys.java:243)
   at org.hibernate.collection.AbstractPersistentCollection.getOrphans(AbstractPersistentCollection.java:930)
   at org.hibernate.collection.PersistentBag.getOrphans(PersistentBag.java:143)
   at org.hibernate.engine.CollectionEntry.getOrphans(CollectionEntry.java:373)
   at org.hibernate.engine.Cascade.deleteOrphans(Cascade.java:471)
   at org.hibernate.engine.Cascade.cascadeCollectionElements(Cascade.java:455)
   at org.hibernate.engine.Cascade.cascadeCollection(Cascade.java:362)
   at org.hibernate.engine.Cascade.cascadeAssociation(Cascade.java:338)
   at org.hibernate.engine.Cascade.cascadeProperty(Cascade.java:204)
   at org.hibernate.engine.Cascade.cascade(Cascade.java:161)
   at org.hibernate.event.def.AbstractFlushingEventListener.cascadeOnFlush(AbstractFlushingEventListener.java:154)
   at org.hibernate.event.def.AbstractFlushingEventListener.prepareEntityFlushes(AbstractFlushingEventListener.java:145)
   at org.hibernate.event.def.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:88)
   at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:50)
   at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1216)