Many programs use a key-value model for configuration options. We examined how this model is used in seven open source Java projects totaling over a million lines of code. We present a static analysis that extracts a list of configuration options for a program. Our analysis finds 95% of the options read by the programs in our sample, making it more complete than existing documentation.
Most conguration options we saw fall into a small number of types. A dozen types cover 90% of options. We present a second analysis that exploits this fact, inferring a type for most options. Together, these analyses enable more visibility into program conguration, helping reduce the burden of configuration documentation and conguration debugging.