Apache Lucene

Apache Lucene has been designed as a powerful, full-text search engine library that can be used virtually with any application that needs full-text search, mainly those cross-platform. The tool is an open source project that has been written entirely in Java.
The software comes with efficient search algorithms, offering support for ranked searches so that users could see the best-matching results returned at the top of the list.
Apache Lucene includes support for a broad range of search query types, including phrases, range, wildcards, and the like. Moreover, it allows users to perform fielded searches and to sort the results by any field.
With the help of this program, users can perform multiple-index searches, and can also take advantage of simultaneous update and searching.
Apache Lucene offers support for highlighting, as well as for joins and result grouping, enables the configuration of storage engine, and is also fast and memory-efficient. Moreover, it includes suggestions that work even with typos.
In addition to featuring low RAM requirements, the software packs high-performance indexing, offering snappy incremental and batch indexing. The size of the index is of around 20-30% of the size of the text that is being indexed.

System requirements