Code Clones: Good, Bad, or Ugly?

Code cloning is often considered as a bad practice in programming, especially from the point of view of maintenance. In this paper we present the results of an empirical study which revealed inverse correspondence between cloning and coupling. Since low coupling is conventionally regarded favourable for maintenance, this finding appears slightly surprising at first sight. In this paper we study the possible benefits of code cloning. Based on a theoretical structural analysis of the effect of cloning, we draw conclusions on the actual, restricted ways cloning is applied in practice.