Mobile environments are characterized by their variable resources (such as network bandwidth), limited amount of resources (memory, processor), and their battery-dependent functioning. These characteristics necessitate the redesign of applications in order to maintain a good quality of service for execution in such environments. Existing approaches provide application-specific solutions which greatly reduces code reuse. Further, mobility issues are embedded in the application functionality making them more difficult to develop and to maintain. In this paper, we propose an object-oriented framework, MolèNE, that provides a set of generic base services as the abstraction of concepts usually utilized to deal with mobility issues. The generic nature of our approach allows services to be customized to different applications. On the other hand, resources management is an important issue in a mobile context. Therefore, MolèNE services have been designed to adapt their behavior depending on resources availability. Moreover, applications needs are taken into account when the adaptation implies the modification of application semantics. All these features make MolèNE a highly adaptable system unique in the mobile computing domain. To illustrate MolèNE use, we present the caching service and its customization for two different applications, a transactional internet application and a file system.