Refactoring support based on code clone analysis

Abstract. Software maintenance is the most expensive activity in soft-ware development. Many software companies spent a large amount of cost to maintain the existing software systems. In perfective mainte-nance, refactoring has often been applied to the software to improve the understandability and complexity. One of the targets of refactoring is code clone. A code clone is a code fragment in a source code that is iden-tical or similar to another. In an actual software development process, code clones are introduced because of various reasons such as reusing code by ‘copy-and-paste ’ and so on. Code clones are one of the factors that make software maintenance difficult. In this paper, we propose a method which removes code clones from object oriented software by us-ing existing refactoring patterns, especially “Extract Method ” and “Pull Up Method”. Then, we have implemented a refactoring supporting tool based on the proposed method. Finally, we have applied the tool to an open source program and actually perform refactoring.