Graph Database in Java (other than Neo4J)

Question

Greetings,
Is there any open source graph database available other than Neo4J??

NOTE: Why not Neo4J?
Neo4J is openso

Answer 1

If your Graphs could be represented as RDF graphs then you could use Jena since that is entirely free and open source

http://jena.sourceforge.net

Whether that's in any way useful to you depends on why you need a Graph database and what type of Graphs you need to store in it.