Apache Solr is the Lucene search server. it encapsulates the Apache Lucene libraries and provides a full-featured enterprise search server. Like Lucene, which it contains, Solr is free open source available under the liberal Apache Software License. Solr and Lucene are built from the same code base within the Apache Lucene project; Solr is essentially the “serverization” of Lucene, and many of its abstract functions are highly similar, if not just the same. Lucene programmers have often reported that they find Solr to contain “the same features I was going to build myself as a framework for Lucene, but already very-well implemented.”

Solr comes ready to run in a servlet container such as Tomcat or Jetty, and ready to scale in a production Java environment. Its RESTful interfaces and XML-based configuration files can greatly accelerate development and streamline maintenance.  Solr provides the following capabilities:

• Web service: Solr places Lucene over HTTP, allowing programs written in any language to invoke Lucene.
• XML based schema for managing indexed fields and their characteristics.
• Admin tools for configuration, data loading, index replication, statistics, logging and cache management
• Large scale distributed search
• Fixed/paid result list placement
• Faceting — the dynamic clustering of items or search results into categories that let users drill into search results (or even skip searching entirely) by any value in any field, as seen in popular e-commerce sites such as Amazon or Zappos.

For most search application development, Solr is the logical starting point, as it encapsulates all of Lucene's search functions -- you might think of Solr as the 'serverization' of Lucene. Java programmers working directly with Lucene have often reported that they find Solr to contain “the same features I was going to build myself as a framework for Lucene, but already very-well implemented.” Once you start with Solr, and you find yourself using a lot of the features Solr provides out of the box, you will likely be better off using Solr’s well-organized extension mechanisms instead of starting from scratch using Apache Lucene.

If you're an experienced open source application developer using Solr, we recommend you download the LucidWorks Certified Distribution for Solr, which includes the latest improvements in a well-packaged, integrated, supportable release curated and tested by the experts at Lucid Imagination.

For production deployments and mission critical applications using Search, LucidWorks Enterprise is the enterprise-grade, supported distribution of Solr, developed by the experts at Lucid Imagination. It builds upon Solr and Lucene  core technolgy with essential complementary features that streamline search application development, enhance user experience with advanced search features, and lower your cost of growth.