java - How do you start derby in network server mode and still get an embedded connection?

Question

I just want to know how I can start derby in network server mode and still be able to get an embedded connection?

Thank you.

Answer 1

You need to launch Derby in "embedded server mode". If you are already using Derby in embedded mode, this can be enabled by providing the necessary files in your classpath, then specifying a handful of command line arguments when launching the application.

First make sure the following jars are in your application's runtime classpath.

     derby.jar derbynet.jar

Then add the following command line options to the Java command used to launch your application. If the class files are missing, these options will have no effect.

    -Dderby.drda.startNetworkServer=true 
    -Dderby.drda.portNumber=8011

I'm running Derby from within a servlet hosted by Tomcat, so I added these options to the catalina.bat file.

Start up your application and check the list of open network sockets.

    netstat -an | find "8011"

You should now see Derby listening for connections on 8011. Its now possible to connect to the database using Derby's client driver (derbyclient.jar). The instructions at http://docs.oracle.com/javadb/10.3.3.0/adminguide/radminembeddedserverex.html cover this part pretty well.

It was hinted that running Derby in this mode may be discouraged. I don't believe that to be the case. Your application will continue to access the database using the embedded driver, while other software is now permitted access using the client driver.