Using a component-based approach, a user task can be defined as an assembly of abstract components (i.e. services), requiring services from and providing services to each other. To achieve the task's execution, it has to be resolved in concrete components, which involves automatic matching and selection of components across various devices. For this goal, we propose in this article a task resolution approach that allows for each service of a user task, the best selection of the device and component used for its execution. The task resolution approach considers in addition to the functional aspects of the task, the user preferences, devices capabilities, services requirements and components preferences. Moreover, applications in pervasive environments are challenged by the dynamism of their execution environments. Towards this challenge, we use a monitoring mechanism to detect the changes of environments and we propose an adaptation approach that is based on the reselection of a subset of devices and components.