Neo4j and Java: demos with an embedded Ne04j graph

After my first experience in installing Neo4j graph database I decided to continue my experiments by writing a little Java demo program. The scope of my program just to learn how to connect to a Neo4j embedded graph, to generate ,connect and query some hundreds of nodes. Neo4j site and the downloaded manual provide plenty of documentation about interfacing with Java, and the other supported languages.

Project set-up

Setting up a Java project is quit simple: just matter of including all Neo4j libraries jars, available in the 'lib' folder, in the project class-path. To make easier future projects set-up I prepared, in Netbeans, a custom library configuration.

Now something completely different: Neo4j

I've been interested in the variegated world of “NOSQL” databases since a while but I was mostly undecided which one start experimenting with. Most of NOSQL databases give their best in high data volumes, high availability, high scalability, “high everything” use cases. Going to test such databases in a realistic way is not an easy task. Testing them on a EEEPC while traveling by train is definitively impossible. I so concentrated my interest on “Graph Databases”: a kind of NOSQL databases designed to represent data tied by complex and deep relationships, hard to be described by the classic table form.

Neo4j

Among the many, Java based, graph databases the one that got my attention has been Neo4j. Two things made me decide for testing Neo4J: first Neo4J is embeddable in your Java project, the second is the huge amount of documentation and examples available at Neo4j site.

Installation

Installing Neo4j has been quite simple just matter of extracting the downloaded archive into a folder in my home directory (I have a “Projects” folder for this)

tar xv neo4j-community-2.0.3-unix.tar.gz

this is more than enough for a test installation or if you are going to use it only embedded in anoter Java project. Installing a Neo4j server would be a little more more tricky.

Neo4j service can be started by shell using the “neo4j” script provided in the bin directory:

cd Projects/neo4j-community-2.0.3/bin/

./neo4j start

at start it gives a warning about not running it in a Oracle Java JVM but during my tests it worked fine even with OpenJDK JVM. Of course fro a more intense use it'd better follow the suggestion and use the right JVM.

The same script can be used to stop Neo4j service:

./neo4j stop

User interface

Neo4j offers a web based user interface on the “http://localhost:7474” address. The web interface provide an easy way to send commands to Neo4j with the help of a good variety of saved scripts and examples available with one mouse click.