Reconfiguring server-side applications while they are up and running is tricky but absolutely essential for many high availability applications. If you are building an IPTV service, the service provider’s customers will not accept a reboot when the provider wants to modify a parameter.

An innovative way of enabling dynamic reconfiguration of high availability applications running in clustered environments will be presented at JavaOne by Peter Kristiansson, Java specialist at Ericsson.

High availability applications include various telecom and communication applications, IPTV services, and applications used in the finance and defense industries. When such applications need to be reconfigured, it is not possible to change the start-up parameters of the application and then restart it, that is, to use so called static reconfiguration. The application needs to keep running uninterrupted while being reconfigured.

“Today’s Java EE standard doesn’t cover the sort of high availability requirements that we at Ericsson  often work with,” Kristiansson says. “End users simply won’t accept that their TV or telephony service is down for reconfiguration. While static reconfiguration is perfectly adequate for many Java EE applications, dynamic reconfiguration is a must in some cases.”

Communication applications in general put high availability requirements on services. For example, chat services in which phone calls and conference calls can be set up.

Peter Kristiansson

Until a high availability standard becomes part of Java EE, developers can build a solution like the one which Kristiansson has specified together with Jens Jensen, an expert in open platform architectures at Ericsson. Their solution, which meets the strictest of high availability requirements, makes it relatively easy to deploy high availability applications.

The solution is based on managed beans, which are part of the Java Management Extensions (JMX) API. Unlike other JMX solutions, Kristiansson’s and Jensen’s solution does not require the application to create the managed beans classes itself. The application only has to create an XML file that describes the structure of managed beans. This file is then read by a back-end, which creates the beans and makes them available to a management console.

“What is unique about our solution is the back-end that we have built which allows the [managed] beans to be created dynamically,” Kristiansson says. “Of course, to use our solution, you will have to build the back end, so this is not a small scale hack.”

Developers interested in the solution can find out more at Kristiansson’s Birds of a Feather session BOF-4945 – “Designing Manageable Java Platform, Enterprise Edition (Java EE platform) Applications in a Clustered Environment” – which is held on Thursday, May 8 at 7:30 pm.

“It will be a mix of an architectural overview of our solution and a tutorial on how to use it,” Kristiansson says.


By Olle Blomberg