We present a canonic model expressing the behavior of a system of communicating objects through multiset rewriting. Then, we discuss the integration of the so-defined model into the Java language. The choices and the restrictions made to implement the model as well as the architecture of the system are presented. Finally, we propose to use the prototype that we carried out as a coordination tool for communicating Java components. We focus on applications built around InfoBus, a standard package providing an event-based protocol for dynamic data-sharing between components. We show how our model can be used to coordinate Java events flowing on a software bus.