Hibernate Collections Lazy Initialization Gotcha

I have some code that looks like this:

AdContent.java (EJB3):

@CollectionOfElements
@JoinTable(name="AdContentSites", 
           joinColumns={@JoinColumn(name="adContentId")})
@Enumerated(EnumType.STRING)
@Column(name="siteName", nullable=false)
@Cache(usage=CacheConcurrencyStrategy.TRANSACTIONAL)
Set siteNames;
public Set getSiteNames() { return this.siteNames; }

This creates a join table called AdContentSites which maps an AdContent object to one or more SiteName's. SiteName is an enum. I then transform AdContent into a POJO called AdContentData and make that available to the web tier.

This is the transform method:

public static AdContentData adContent(AdContent raw)
{
        // Need to lazily initialize the collection
        raw.getSiteNames().size();
   
        AdContentData adc = new AdContentData(
                                   raw.getId(),
                                   raw.getName(),
                                   raw.getContent(),
                                   raw.getSiteName(),
                                   raw.getStart(),
                                   raw.getEnd(),
                                   raw.getCreatedBy(),
                                   raw.getCreated());
        return adc;
}

The part that bit me in the ass for a while was the fact that Hibernate lazily populates Collections. I kept getting the less than helpful error: "failed to lazily initialize a collection of role: com.kink.heart.entity.adn.AdContent.siteNames, no session or session was closed"

The solution (as you can see above) was to force Hibernate to initialize the Collection by calling AdContent.getSiteName().size(). Maybe it is just me, but I would have expected the call further down to raw.getSiteNames() to do that work for me, but I guess because of the way the object proxy works, that isn't what is going to happen.