no-herd Arsen.Shnurkov@gmail.com Lucene.Net is a source code, class-per-class, API-per-API and algorithmatic port of the Java Lucene search engine to the C#. In addition to the APIs and classes port to C#, the algorithm of Java Lucene is ported to C# Lucene. This means an index created with Java Lucene is back-and-forth compatible with the C# Lucene; both at reading, writing and updating. In fact a Lucene index can be concurrently searched and updated using Java Lucene and C# Lucene processes.