Lucene, Open-source search software

http://lucene.apache.org/

The Apache Lucene project develops open-source search software, including:

• Lucene Java, our flagship sub-project, provides Java-based indexing and search technology, as well as spellchecking, hit highlighting and advanced analysis/tokenization capabilities.
• Solr is our high performance enterprise search server, with XML/HTTP and JSON/Python/Ruby APIs, hit highlighting, faceted search, caching, replication, database integration, web admin and search interfaces.
• Lucene.Net is a source code, class-per-class, API-per-API and algorithmatic port of the Lucene Java search engine to the C# and .NET platform utilizing Microsoft .NET Framework. Lucene.Net is currently under incubation.
• PyLucene is a Python port of the the Lucene Java project.
• Open Relevance Project is a subproject with the aim of collecting and distributing free materials for relevance testing and performance.
• Lucy is a loose C port of Lucene Java, with Perl and Ruby bindings, currently in incubation.
• Droids is an intelligent robot crawling framework currently in incubation.