Stardog is the easiest, most powerful graph database: search, query, reasoning, and constraints in a lightweight, pure Java system.
Unmatched query performance
ACID, Integrity Constraints, RBAC security
For continuous operations
Supports OWL 2 and user-defined rules
Full text, semantically typed search out of the box
Data unification for RDBMS data
Graph traversals and algorithms with Gremlin
Smart query answering for location-aware graphs
Stardog is an enterprise graph database:
SPARQL for queries; OWL for reasoning;
pure Java for the Enterprise.