Since the concept of grid computing has emerged; one of the major challenges consists in making applications able to benefit efficiently from the huge amount of resources with out burdening the developer. Observing that grid computing environments are dynamic, adaptability has been proposed as a way to tackle this problem. Adaptability is in deed the ability of applications to modify themselves according to their actual environment. It guarantees that they continuously behave in the best possible way despite environmental changes. In the context of grid computing, environmental changes concern mostly processor and network availability because of resource sharing between applications, administrative tasks and failures