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