Full text search engines like Apache Lucene are very powerful technologies to
add efficient free text search capabilities to applications. However, Lucene
suffers several mismatches when dealing with object domain models. Amongst
other things indexes have to be kept up to date and mismatches between index
structure and domain model as well as query mismatches have to be avoided.

Hibernate Search addresses these shortcomings - it indexes your domain model
with the help of a few annotations, takes care of database/index
synchronization and brings back regular managed objects from free text queries.

Hibernate Search is using Apache Lucene under the cover.