The term Lucene refers to the open source Java fulltext search engine library, but also to the entire eco-system that grew around it, including lucene.net, solr, elasticsearch and zend-search-lucene.
The term "Lucene" refers to the open source Java fulltext search engine library, and also to the entire eco-system that grew around it, including lucene.net, solr, 
elasticsearch and zend-search-lucene. "Lucene" may also be used to refer to top-level projects like Nutch and Tika which were once sub-projects of Lucene.
Use the "Lucene" tag if either:
- The question is about the Java library
- The question is about a port of the library, but would make sense to people who know the Java library (many Lucene.NET questions match this criteria).
- The question is so general it doesn't apply to a specific implementation (example).
References:
Basic Demo:
A basic "getting started" demo showing how to build and query an index is provided as part of the official documentation:
Basic Demo documentation - (this link is for Lucene v8.7.0. Newer versions may be available)
Links to the demo's source files are provided in the above documentation.
The source code can also be found here on GitHub.
Luke - a Lucene GUI Client:
Luke is a GUI client application which can be used to explore your Lucene indexes. Recent versions of Luke are now provided as part of each binary release, which can be downloaded from here.
After downloading the binary release, unzip it, and go to the luke directory. Launch the client using the provided luke.bat or luke.sh scripts.
