Is there a best practice for storing versions of objects?

I have a user configuration object that I want to be able to persist. There will be one active object, but many previous ones reflecting the state of their configuration at that point in time. When the user makes updates to their configuration, I want to make a new version of the object in the database. The obvious way to me is to make a deep copy and then use the usual save semantics. However, I was wondering if there is a way to detach the object and then save it so that it will get a new id and the old version will still be in the database and I avoid the deep copy?

Thanks,
Grant

I would say that if you detach it, set the primary key to null and then save it, hibernate would insert a new entry, since it thinks it is a new instance because the primary key is null.

Here's what I did and it seems to work:

...
if (sess.contains(userConfiguration))
{
sess.evict(userConfiguration);
userConfiguration.setId(new Long(-1));//the unsaved-value is -1
}
result = (Long) sess.save(userConfiguration);