An Empirical Study on Accidental Cross-Project Code Clones

Software clones are considered a code smell in software development. While most clones occur due to developers copy - paste behaviour, some of them arise accidentally as a symptom of coding idioms. If such accidental clones occur across projects, then they may indicate a lack of abstraction in the underlying programming language or libraries. In this research, we study accidental cross-project clones from the perspective of missing abstraction. We discuss the six cases of frequent cross-project clones, three of them symptoms of missing language features (which have been resolved with the release of Java 7 and Java 12), and two of them symptoms of missing library features (which have not yet been addressed).