Hibernate Search

Hibernate Search brings the power of full text search engines to the persistence domain model and Hibernate experience, through transparent configuration (Hibernate Annotations) and a common API.

Full text search engines like Apache Lucene(tm) allow applications to execute free-text search queries. However, it becomes increasingly more difficult to index a more complex object domain model - keeping the index up to date, dealing with the mismatch between the index structure and the domain model, querying mismatches, and so on.