The purpose of this thesis is to study distributed applications in the context of heterogeneous clients (Web browser, mobile) and business-to-business (B2B) integration. Two distributed architectures, leaders of the distributed applications market are presented and compared: Microsoft's .NET, and Sun's Java Enterprise Java Beans (J2EE). After this comparative study, we chose .NET to develop an e- commerce application (Jurasco Style electronic shop) in order to outline the major application architectural issues and solutions offered by .NET technology. Our study also shows how the .NET Jurasco ...