A Directory is the most common abstraction used by Lucene to represent the index storage; Hibernate Search doesn't interact directly with a Lucene Directory but abstracts these interactions via an IndexManager: an index does not necessarily need to be implemented by a Directory.

If you know your index is represented as a Directory and need to access it, you can get a reference to the Directory via the IndexManager. Cast the IndexManager to a DirectoryBasedIndexManager and then use getDirectoryProvider().getDirectory() to get a reference to the underlying Directory. This is not recommended, we would encourage to use the IndexReader instead.