Advanced clone-analysis to support object-oriented system refactoring

Manual source code copy and modification is often used by programmers as an easy means for functionality reuse. Nevertheless, such practice produces duplicated pieces of code or clones whose consistent maintenance might be difficult to achieve. It also creates implicit links between classes sharing a functionality. Clones are therefore good candidates for system redesign. This paper presents a novel approach for computer-aided clone-based object-oriented system refactoring. The approach is based on an advanced clone analysis which focuses on the extraction of clone differences and their interpretation in terms of programming language entities. It also focuses on the study of contextual dependencies of cloned methods. The clone analysis has been applied to JDK 1.1.5, a large scale system of 150 KLOC.