OPSS Service's or a Proxy (TenantContextManager) should implement this interface if service wants to be able to listen to configuration changes made by the Management Config Beans. The idea is that an OPSS Service is generally implemented by a bunch of classes and and hence having a Listener based approach will provide flexibility in Config Change handling. An alternative approach is for the ServiceInstance to export a method of the form handleConfigChanges(PropertyChangeEvent[] changes). But that would require the ServiceInstance to orchestrate and ensure each change is passed on to the right subcomponent of the Service Implementation.