In this demonstration we show drag-and-drop distribution of centralized, modular Java applications. Our system is based on OSGi, an industry standard for building Java applications out of modular units loosely connected through services. Since OSGi is a centralized system, we have elaborated a solution to seamlessly distribute OSGi applications along the boundaries of services and thereby turning arbitrary OSGi applications into distributed applications. In this demonstration, we present an Eclipse based tool that takes the source code of an OSGi application as input, produces a graph of its modules and module dependencies, and allows the user to deploy the application across a distributed system by dragging-and-dropping its constituent modules on different machines. By defining constraints on the distribution, the tool can also support advanced features like load-balancing or redundancy of modules.@en

In this paper we take advantage of the concepts developed for centralized module management, such as dynamic loading and unloading of modules, and show how they can be used to support the development and deployment of distributed applications. We do so through R-OSGi, a distributed middleware platform that extends the centralized, industry-standard OSGi specification to support distributed module management. To the developer, R-OSGi looks like a conventional module management tool. However, at deployment time, R-OSGi can be used to turn the application into a distributed application by simply indicating where the different modules should be deployed. At run time, R-OSGi represents distributed failures as module insertion and withdrawal operations so that the logic to deal with failures is the same as that employed to deal with dependencies among software modules. In doing so, R-OSGi greatly simplifies the development of distributed applications with no performance cost. In the paper we describe R-OSGi and several use cases. We also show with extensive experiments that R-OSGi has a performance comparable or better than that of RMI or UPnP, both commonly used distribution mechanisms with far less functionality than R-OSGi.@en