D.: Using Fail-stop Proxies for Enhancing Services Isolation

The OSGi Service Platform is becoming the de facto middle-ware for deploying modularized Java applications. It is a dy-namic platform that relies on a service oriented approach for loose coupling, but the absence of separate object spaces for isolating services of different modules cannot guarantee that service providers from uninstalled modules will no longer be referenced by active code. This may lead to memory reten-tion and inconsistencies (e.g. a stale service that provides invalid cached data) that can introduce silent faults in the system by propagating invalid information. We present our ongoing work where we introduce an iso-lation layer between service consumer and provider by us-ing dynamic proxies for services. When the corresponding service becomes unregistered (i.e. uninstalled) the mecha-nism is able to: 1) Guarantee that no consumers directly refer to the service provider; 2) allow finding out the mis-referencing consumer code by using a fail-stop mechanism. We present tested in different OSGi based applications and benchmarked against other approaches for accessing services in the OSGi platform