About me

I am a member of the Software Engineering Group at the University of Bremen, Germany. Currently, I am working on my doctoral thesis under the supervision of Prof. Dr. Rainer Koschke.

Research

My main research focus are source code clones and their effect on the maintainability of software. Clones are believed to be one of the most severe bad smells in programming. Recent research has indeed revealed some situations in which clones may negatively affect maintainability. But in systematic studies—including my own research—we did not observe that clones have such a negative effect in general.

Obviously, clones are diverse and there is no universal means to handle them. I am interested in empirical studies on clones to learn more about their effects on maintainability and to seek for for properties that may make clones a threat. While duplicated code may cause problems, cloning is also an indispensable strategy in programming. The balance of pros and cons is another research interest of mine.

Beyond code clones I am interested in bad code smells, software maintenance and software quality in general.

Tools

Our group develops some great tools to detect, analyze, and inspect clones, which are freely available for academic use. Please visit our website softwareclones.org to learn more.

Contact

Publications

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  Jan Harder. Code Clone Authorship–A First Look. 14th Workshop Software Reengineering, 2012.

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  Jan Harder, Rebecca Tiarks. A Controlled Experiment on Software Clones. 20th International Conference on Program Comprehension, pages 37–46, IEEE, 2012.

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  Cory Kapser, Jan Harder, Ira Baxter. A Common Conceptual Model for Clone Detection Results. 6th International Workshop on Software Clones, 2012.

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  Jan Harder and Nils Göde. Cloned code: stable code. Journal of Software: Evolution and Process, 2012. [Online].

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  Nils Göde and Jan Harder. Oops!... I Changed It Again. In Proceedings of the 5th International Workshop on Software Clones, pages 14–20. ACM, 2011.

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  Jan Harder and Nils Göde. Efficiently Handling Clone Data: RCF and Cyclone. In Proceedings of the 5th International Workshop on Software Clones, pages 81–82. ACM, 2011.

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  Jan Harder, Nils Göde, and Marcus Rausch. Stability of COBOL Clones. Softwaretechnik-Trends, 31(2):24–25, 2011.

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  Nils Göde and Jan Harder. Clone Stability. In Proceedings of the 15th European Conference on Software Maintenance and Reengineering, pages 65–74. IEEE Computer Society, 2011.

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  Jan Harder and Nils Göde. Quo Vadis, Clone Management? In Proceedings of the 4th International Workshop on Software Clones, pages 85–86. ACM, 2010.

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  Jan Harder and Nils Göde. Modeling Clone Evolution. In Proceedings of the 3rd International Workshop on Software Clones, pages 17–21. IEEE Computer Society, 2009.

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  Jan Harder, Rainer Koschke. Empirische Grundlagen für das Klonmanagement. Lecture Notes in Informatics (LNI), Proceedings of 10th Workshop Software Reengineering (P-126), pages 127-133., 2008.

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  Jan Harder. Rückgewinnung von Syntax und Semantik zur Analyse von Visual Basic 6 Programmen. Softwaretechnik-Trends, 27(2), 2007.

Other Activities

• Tool Demonstrations Program Committee, ICSM 2012: 28th International Conference on Software Maintenance
• Publicity Chair, IWSC 2012: 6th International Workshop on Software Clones
• Additional Reviewer, ASE 2010: International Conference on Automated Software Engineering