14. Connections

All core RDFox® functionality is accessed through connections. Server operations are accessed through server connections while data store operations are accessed through data store connections.

Obtaining an initial server or data store connection requires authenticating as one of the server’s roles. Thereafter, clients can create additional connections using the same role without re-authenticating by duplicating an existing connection or by creating data store connections from a server connection.

In general, connections are designed for use from one thread at a time. That is, while connections have no affinity to particular threads, calling connection methods concurrently from more than one thread will generally result in undefined behavior including crashes. Specific exceptions to this rule exist to support duplication of connections, password verification and the interruption of operations active on a particular connection.


A data store cannot be deleted while there are open connections to it. For this reason, and to minimize resource usage, connections should be closed when no longer needed.

While the above characteristics of connections are true regardless of which RDFox interface (shell, REST or Java) is being used, each interface has its own specific mechanisms for managing connections. For details of connection management in the shell see Section 15.1. For details of how connections are created by the endpoint see Section 16.2.3 and Section 16.2.4. For information about how to create connections in Java, see the API documentation for the ConnectionFactory class.