In the paper we present a technology for development of dynamic multi-agent systems which is based on a combination of the object-oriented approach with constraint programming. We introduce the notion of an active object as a way of describing and implementing the intellectual, reactive and communicative properties of agents. We describe computation processes in active objects. A special emphasis is made on the dynamic component of this technology. Dynamic systems are classified with respect to their complexity level. It is shown how such systems can be implemented with the help of the technology of active objects.