In the last four years, our research project dealt with separation of concerns for distributed programming environments and applications. This research effort led to the implementation of the Java Aspect Component (JAC) framework for aspect-oriented programming (AOP) in Java. Among the many requirements for distribution, flexibility and adaptability play a stringent role. The high variability of executing conditions (in terms of resources, servers availability, faults, ...) also brings the need for powerful programming paradigms. This led us to develop a dynamic model of AOP which, unlike statically compiled approaches, allows to on-the-fly deploy and undeploy aspects on top of running applications. This model comes with an UML notation and an implementation. An IDE is provided with JAC to support all the development steps of an aspect oriented application, from its design, to its implementation, to its deployment.