Dynamic Service Update Based on OSGi

In the OSGi framework, the service updating is achieved by updating the cooperating bundles. However, the way of service updating requires a temporary shutdown of bundles and can not implement the transfer of service´s states. Thus it is not really dynamic service update. In this paper, we present two techniques to solve the problem of dynamically updating service in OSGi. One technique is replacing the service through interacting with other service with the same name. The other technique is based on the combination of runtime source compilation, class reloading and the proxy design pattern. The technique only needs modification of source code and little manual changes. Finally, we also prove the dynamic service updating is type-safe if preserving the service dependency relationships after updates.