Components of object-oriented systems have strong similarities with components of distributed systems; objects can be viewed as loosely coupled computing entities similar to distributed processes, but objects granularity is generally different from process granularity. This prevents a direct mapping between objects and processes during the implementation process. This paper presents a suitable coordination model, based on hierarchical execution contexts, allowing to map object-oriented specifications into distributed systems. As a result, object-oriented systems can be mapped into distributed systems at the specification level, and we obtain a formal framework for understanding and implementing distributed systems.