the hibernate gateway is used in a similar fashion to the sql gateway but differs in that it does not use plain sql, and in that instead of polling a table with a specified interval the hibernate gateway does not need to poll. It uses interceptors that will be notified upon events (onSave, onDelete, onLoad, onFlushDirty, onCollectionUpate, onCollectionRemove).
When an event is triggered it will package the entity into an ESB Message object and invoke the action pipeline. This packaging is the default behavior but can be overridden if needed.
TomC, anything that I've left out?
For an example of the hibernate gateway checkout the helloworld_hibernate_action quickstart.