KOWALSKI: Collecting API Clients in Easy Mode

Understanding API usage is important for upstream and downstream developers. However, compiling a dataset of API clients is often a tedious task, especially since one needs many clients to draw a representative picture of the API usage.In this paper, we present KOWALSKI, a tool that takes the name of an API, then finds and downloads client binaries by exploiting the Maven dependency management system. As a case study, we collect clients of Apache Lucene, the de facto standard for full-text search, analyze the binaries, and create a typed call graph that allows developers to identify hotspots in the API.A video demonstrating how KOWALSKI is used for this experiment can be found at https://youtu.be/zdx28GnoSRQ.