Search.session() creates a LazyInitSearchSession that retrieves the actual underlying SearchSession lazily upon first access, and then caches it.

This means that, if you call Search.session on a Session proxy that relies on thread-locals to redirect calls to the actual session (e.g. sessionFactory.getCurrentSession(), or Spring EntityManager proxies), the resulting SearchSession will always delegate to the Session from the first thread. This is problematic for many reasons: thread-safety (a session will be accessed from concurrent threads), search (we'll retrieve entities from an unrelated session), indexing (we'll add indexing operations to the wrong session/transaction), ...