JPOX supports 3 modes of operation of db4o - file-based, embedded-server-based and TCP/IP-server based. In order to do so and to fit in with the JDO/JPA APIs we have defined the following means of connection.

The following connection properties will connect to a local file-based DB4O running on your local machine

javax.jdo.option.ConnectionDriverName=
javax.jdo.option.ConnectionURL=db4o:file:{my_db4o_file}
javax.jdo.option.ConnectionUserName=
javax.jdo.option.ConnectionPassword=

The filename can be absolute OR relative.

For EmbeddedServer-based DB4O you would specify it as follows

javax.jdo.option.ConnectionDriverName=
javax.jdo.option.ConnectionURL=db4o:server:{my_db4o_file}
javax.jdo.option.ConnectionUserName=
javax.jdo.option.ConnectionPassword=

Again, the filename can be absolute OR relative.

The following JDO connection properties will connect as a client to a DB4O TCP/IP server

javax.jdo.option.ConnectionDriverName=
javax.jdo.option.ConnectionURL=db4o:{db4o_host}:{db4o_port}
javax.jdo.option.ConnectionUserName=
javax.jdo.option.ConnectionPassword=

DB4O doesn't itself use such URLs so it was necessary to define this JPOX-specific way of addressing DB4O.