The Reaction of Open-Source Projects to New Language Features: An Empirical Study of C# Generics

Language designers introduce new language features in programming languages because those features are claimed to be bene cial. In this paper, we investigate claims made about the generics language feature, and compare how those claims stack up in C# versus Java. Through an empirical study of the generics feature in open-source projects, we found that (1) although they have the same claimed bene ts in di erent programming languages, generics are more readily used in C# than in Java and that the bene ts of generics are manifested more clearly in C# programs, and (2) programmers rarely use the var keyword with generics, except when using very long generic expressions, suggesting that programmers prefer readability over succinct syntax, as long as the syntax does not become overly verbose. Many of these observed di erences may be attributed to subtle di erences in implementation and are consistent with the notion that crafting the user experience of a programming language feature can impact how the feature is adopted and embraced by developers.