A full-featured text search engine. Including starting guide, mailing list signup, and API documentation. [Open source, BSD-like]

Supplies basic search capabilities for Web use. [Open Source, BSD-like]

Search engine with many features including fast indexing, ranked searching, boolean and phrase queries, date-range searching, and extension APIs. [Open Source, BSD-like]

Full featured text search engine for web sites, completely in Java. Can be easy integrated into any web site. Supports XML, XSLT, EJB. [Freeware]

Servlet acting as a search engine for small websites. [Open Source]

A search application designed on a robust Java architecture. Results are delivered in a fast and relevant manner. SearchBlox is deployable on any Servlet 2.3/JSP 1.2 compliant server. [Commercial]