The high volatility and competitively of organizational ('socio-techno-economical') environment are putting tremendous pressure on software-intensive developers to come up with adaptive and evolving approaches. To contribute to such topical efforts towards adaptive information system at early phases, the present thesis addresses the rigorous development of self-adapting information systems. The approach we are putting forwards is referred to as RAMSES(Reflective and Adaptive Middleware for Software Evolution of non-stopping information Systems), and provides a reflective architecture for adapting the software applications, in response the requirements and environmental changes. The reflective middleware is based on a UML-compliant base- and meta-level. RAMSES provides objects with the ability of dynamically changing their behavior by exploiting their design information. The meta-level of the proposed architecture reifies UML diagrams including structural and behavioral information of the system to adapt; then it uses such data for dynamically adapting the software system against environmental changes. The evolution takes place in two steps: a meta-object, called evolutionary meta-object, plans a possible evolution against the detected external events then another meta-object, called consistency checker meta-object validates the feasibility of the proposed plan before really evolving the system. The meta-objects use the system design information to lead its evolution. Our middleware uses reification library to explicit an abstract view of the concrete-level that can be manipulated at run-time. Both evolutionary and consistency checker meta-objects work directly on the reifications. The evolutionary meta-object steers the evolution of reifications through evolutionary rules that describe the changes in environment. Where as the consistency checker meta-object check the reifications are consistent with the changes. To evaluate RAMSES and validate our claims, a number of examples of urban traffic control system (UTCS) are used.