Neo4j is an open source NOSQL graph database, implemented in Java. It saves data structured in graphs rather than in tables.
It is one of the most popular open-source free NOSQL Graph DBMS (database management system) developed by Neo4j, Inc. It written in Java and Scala..The development of Neo4j was started in 2003, it has been publicly available since 2007. The source code and issue tracking of Neo4j is available on GitHub, with support readily available on Stack Overflow and the Neo4j Google group.
