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   <h1 class="title">Apache Lucene Core</h1>
   <p>Apache Lucene™ is a
 high-performance, full-featured search engine library written entirely in Java.
 It is a technology suitable for nearly any application that requires structured
 search, full-text search, faceting, nearest-neighbor search across
 high-dimensionality vectors, spell correction or query suggestions.</p>
 <p>Apache Lucene is an open source project available for free download. Please use the
 links on the right to access Lucene.</p>
 <h1 id="lucenetm-features">Lucene™ Features</h1>
 <p>Lucene offers powerful features through a simple API:</p>
 <h2 id="scalable-high-performance-indexing">Scalable, High-Performance Indexing</h2>
 <ul>
 <li>over <a href="http://home.apache.org/~mikemccand/lucenebench/indexing.html">800GB/hour on modern hardware</a></li>
 <li>small RAM requirements -- only 1MB heap</li>
 <li>incremental indexing as fast as batch indexing</li>
 <li>index size roughly 20-30% the size of text indexed</li>
 </ul>
 <h2 id="powerful-accurate-and-efficient-search-algorithms">Powerful, Accurate and Efficient Search Algorithms</h2>
 <ul>
 <li>ranked searching -- best results returned first</li>
 <li>many powerful query types: phrase queries, wildcard queries, proximity
   queries, range queries and more</li>
 <li>fielded searching (e.g. title, author, contents)</li>
 <li>nearest-neighbor search for high-dimensionality vectors</li>
 <li>sorting by any field</li>
 <li>multiple-index searching with merged results</li>
 <li>allows simultaneous update and searching</li>
 <li>flexible faceting, highlighting, joins and result grouping</li>
 <li>fast, memory-efficient and typo-tolerant suggesters</li>
 <li>pluggable ranking models, including the <a href="http://en.wikipedia.org/wiki/Vector_Space_Model">Vector Space Model</a> and <a href="http://en.wikipedia.org/wiki/Okapi_BM25">Okapi BM25</a></li>
 <li>configurable storage engine (codecs)</li>
 </ul>
 <h2 id="cross-platform-solution">Cross-Platform Solution</h2>
 <ul>
 <li>Available as Open Source software under the <a href="https://www.apache.org/licenses/LICENSE-2.0.html">Apache License</a> which lets you use
   Lucene in both commercial and Open Source programs</li>
 <li>100%-pure Java</li>
 <li>Implementations <a href="https://cwiki.apache.org/confluence/display/lucene/LuceneImplementations">in other programming languages available</a> that are index-compatible</li>
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   <li><a href="http://mahout.apache.org">Apache Mahout</a></li>
   <li><a href="http://nutch.apache.org">Apache Nutch</a></li>
   <li><a href="http://opennlp.apache.org/">Apache OpenNLP</a></li>
   <li><a href="http://tika.apache.org">Apache Tika</a></li>
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	<div class="slideshow" id="mantleSlides">
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	Ultra-fast Search Library<br/>
	</div>
	<div class="descwrapper">
	<div class="description">
	Apache Lucene sets the standard for search and indexing performance
	</div>
	</div>
	<div class="mantle">
	<img alt="Apache Lucene" src="/theme/images/lucene/core/mantle-lucene.png?v=0e493d7a"/>
	</div>
	</div>
	<div id="slide2" style="display:none">
	<div class="callout">
	Proven search capabilities<br/>
	</div>
	<div class="descwrapper">
	<div class="description">
	Lucene is the de facto standard for search libraries
	</div>
	</div>
	<div class="mantle">
	<img alt="Lucene Power" src="/theme/images/lucene/mantle-power.png?v=0e493d7a"/>
	</div>
	</div>
	<div id="slide3" style="display:none">
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	Innovation and Maturity
	</div>
	<div class="descwrapper">
	<div class="description">
	Lucene has proven stability as well as a track record of innovation
	</div>
	</div>
	<div class="mantle">
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	<div id="content-wrap" class="clearfix">
	<div id="main">
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	<h1 class="title">Apache Lucene Core</h1>
	<p>Apache Lucene™ is a
	high-performance, full-featured search engine library written entirely in Java.
	It is a technology suitable for nearly any application that requires structured
	search, full-text search, faceting, nearest-neighbor search across
	high-dimensionality vectors, spell correction or query suggestions.</p>
	<p>Apache Lucene is an open source project available for free download. Please use the
	links on the right to access Lucene.</p>
	<h1 id="lucenetm-features">Lucene™ Features</h1>
	<p>Lucene offers powerful features through a simple API:</p>
	<h2 id="scalable-high-performance-indexing">Scalable, High-Performance Indexing</h2>
	<ul>
	<li>over <a href="http://home.apache.org/~mikemccand/lucenebench/indexing.html">800GB/hour on modern hardware</a></li>
	<li>small RAM requirements -- only 1MB heap</li>
	<li>incremental indexing as fast as batch indexing</li>
	<li>index size roughly 20-30% the size of text indexed</li>
	</ul>
	<h2 id="powerful-accurate-and-efficient-search-algorithms">Powerful, Accurate and Efficient Search Algorithms</h2>
	<ul>
	<li>ranked searching -- best results returned first</li>
	<li>many powerful query types: phrase queries, wildcard queries, proximity
	queries, range queries and more</li>
	<li>fielded searching (e.g. title, author, contents)</li>
	<li>nearest-neighbor search for high-dimensionality vectors</li>
	<li>sorting by any field</li>
	<li>multiple-index searching with merged results</li>
	<li>allows simultaneous update and searching</li>
	<li>flexible faceting, highlighting, joins and result grouping</li>
	<li>fast, memory-efficient and typo-tolerant suggesters</li>
	<li>pluggable ranking models, including the <a href="http://en.wikipedia.org/wiki/Vector_Space_Model">Vector Space Model</a> and <a href="http://en.wikipedia.org/wiki/Okapi_BM25">Okapi BM25</a></li>
	<li>configurable storage engine (codecs)</li>
	</ul>
	<h2 id="cross-platform-solution">Cross-Platform Solution</h2>
	<ul>
	<li>Available as Open Source software under the <a href="https://www.apache.org/licenses/LICENSE-2.0.html">Apache License</a> which lets you use
	Lucene in both commercial and Open Source programs</li>
	<li>100%-pure Java</li>
	<li>Implementations <a href="https://cwiki.apache.org/confluence/display/lucene/LuceneImplementations">in other programming languages available</a> that are index-compatible</li>
	</ul>
	</div>
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	</div>
	<div class="download-desc">Apache Lucene 9.10.0</div>
	</div>

	<h1 id="resources">Resources</h1>
	<ul>
	<li><a href="/core/discussion.html">Mailing Lists</a></li>
	<li><a href="/core/developer.html">Developer</a></li>
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	<li><a href="/core/downloads.html">Releases</a></li>
	<li><a href="/core/systemreqs.html">System Requirements</a></li>
	</ul>

	<h1 id="release-docs">Release Docs</h1>
	<ul>
	<li><a href="/core/9_10_0/index.html">9.10.0</a></li>
	</ul>

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	<h1 id="asf-links">ASF links</h1>
	<ul>
	<li><a href="https://www.apache.org">Apache Software Foundation</a></li>
	<li><a href="https://www.apache.org/foundation/thanks.html">Thanks</a></li>
	<li><a href="https://www.apache.org/foundation/sponsorship.html">Become a Sponsor</a></li>
	<li><a href="https://www.apache.org/security/">Security</a></li>
	</ul>

	<h1 id="related-projects">Related Projects</h1>
	<ul>
	<li><a href="https://solr.apache.org">Apache Solr</a></li>
	<li><a href="http://hadoop.apache.org">Apache Hadoop</a></li>
	<li><a href="http://manifoldcf.apache.org/">Apache ManifoldCF</a></li>
	<li><a href="http://lucenenet.apache.org/">Apache Lucene.Net</a></li>
	<li><a href="http://mahout.apache.org">Apache Mahout</a></li>
	<li><a href="http://nutch.apache.org">Apache Nutch</a></li>
	<li><a href="http://opennlp.apache.org/">Apache OpenNLP</a></li>
	<li><a href="http://tika.apache.org">Apache Tika</a></li>
	<li><a href="http://zookeeper.apache.org">Apache Zookeeper</a></li>
	</ul>

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