Lucene is an Open Source, mature and high-performance Java search engine. It is highly flexible, and scalable from hundreds to millions of documents.

Luke is a handy development and diagnostic tool, which accesses already existing Lucene indexes and allows you to display and modify their content in several ways:

• browse by document number, or by term
• view documents / copy to clipboard
• retrieve a ranked list of most frequent terms
• execute a search, and browse the results
• analyze search results
• selectively delete documents from the index
• reconstruct the original document fields, edit them and re-insert to the index
• optimize indexes
• open indexes consisting of multiple parts, and located on Hadoop filesystem
• and much more...

Current stable release of Luke is 3.5.0 and it includes Lucene 3.5.0 and Hadoop 0.20.2. Available is also Luke 1.0.1 (using Lucene 3.0.1), 0.9.9.1 based on Lucene 2.9.1, and other versions as well - please see the Downloads section.

Luke releases are numbered the same as the version of Lucene libraries that they use (plus a minor number in case of bugfix releases).

Below is a screenshot of the application showing the Overview section, which displays the details of the index format and some overall statistics.

Luke Overview tab