  In this paper we propose a systematic strategy for migrating crosscutting
concerns in existing object-oriented systems to aspect-based solutions. The
proposed strategy consists of four steps: mining, exploration, documentation
and refactoring of crosscutting concerns. We discuss in detail a new approach
to aspect refactoring that is fully integrated with our strategy, and apply the
whole strategy to an object-oriented system, namely the JHotDraw framework. The
result of this migration is made available as an open-source project, which is
the largest aspect refactoring available to date. We report on our experiences
with conducting this case study and reflect on the success and challenges of
the migration process, as well as on the feasibility of automatic aspect
refactoring.
