SOLR – Recommended Open Source Enterprise Search Server

SOLR – Recommended Open Source Enterprise Search Server:
I recently came across SOLR enterprise search server. It is based on the Lucene Java search library, with XML/HTTP and JSON APIs, hit highlighting, faceted search, caching, replication, and a web administration interface. It runs in a Java servlet container such as Tomcat.
List of Available Features: http://lucene.apache.org/solr/features.html
Tutorial: http://lucene.apache.org/solr/tutorial.html