Hi Anthony

The Jazz client is built on Eclipse, which is itself built on OSGi/Equinox. So the Jazz client is composed of OSGi bundles/plug-ins. In this regard the Jazz client is just like any other Eclipse client.

The Jazz server is built on OSGi/Equinox running inside a servlet container. The Jazz server is also comprised of OSGi bundles/plug-ins, but they go further in that they leverage OSGi services.

In the early days of the Jazz server OSGi services were not used, but the concept of a "service" did exist. Services were declared using the <serviceProvider> extension point, but there was no way to declare a service's prerequsites, amongst other things.

Today a Jazz service is still declared using the <serviceProvider> extension point, but you can now defined prerequsites that can be a <requiredService> or an <optionalService>. So the XML for the <serviceProvider> extension point has evolved, and each <serviceProvider> is now registered as an OSGi service. By leveraging OSGi sevice we are able to honor the service's prerequisites, notifying the service when all its prerequisites are avilable, and notifying the service when its prerequistes are no longer available. Also, a prerequisite of a service is simply another service, regardless of whether it was registered on your behalf though the <serviceProvider> extension point, or natively using the OSGi APIs. They're all just OSGi services, the platform does not care.

I hope this helps.

Simon