API Design Implications of Boilerplate Client Code

Designing usable APIs is critical to developers' productivity and software quality but is quite difficult. In this paper, I focus on "boilerplate" code, sections of code that have to be included in many places with little or no alteration, which many experts in API design have said can be an indicator of API usability problems. I investigate what properties make code count as boilerplate, and present a novel approach to automatically mine boilerplate code from a large set of client code. The technique combines an existing API usage mining algorithm, with novel filters using AST comparison and graph partitioning. With boilerplate candidates identified by the technique, I discuss how this technique could help API designers in reviewing their design decisions and identifying usability issues.