Recent research advances in the field of reflective middleware systems, autonomous software agent, advanced software engineering and control engineering are contributing to a better understanding of adaptive software. Though, still further work is required to understand and develop high-level languages, protocols and associated tools for ad-hoc and opportunistic software self-servicing capabilities. This paper describes on-going research aiming at the development of a framework for self-adaptive middleware software services. The framework exploits service-oriented programming and computational intelligence to support software systems self-governance through dynamic reconfiguration using agent assembly models. The paper will present a brief overview of Jini basic mechanisms and their use to support the development of the impromptu framework. This will be followed by a description of our approach and concluding remarks.