If I want to override \ extend the default behavior of Hibernate Search
Which behavior in particular do you want to override? There are several things you
can configure and/or provide custom implementations for.
Is there a way to get & use the IndexWriter that Hibernate Search uses?
Are there any interceptors \ hooks for the update \ delete operations?
There is no way to get hold of the IndexWriter. Potentially you could implement a custom
BackendQueueProcessor, but it all depends on what you want to do.
Can you provide some more details about your usecase?