Most people have heard of application visualization, but few have heard of application sonification. Just as an auto mechanic can listen to a car and often hear what’s wrong, Log4JFugue lets you listen to your application in the background—while attending to more important tasks.

By converting a program’s log4j output into a JFugue music stream, developers gain new insights into programmatic behavior. Log4jFugue consists of a core engine written in Java and Groovy, which is then configured using Spring. Every program has a key set of log messages corresponding to its primary verbs—such as “create a thing,” “process a thing,” “destroy a thing,” “get an error.” Each of these log messages is configured and associated with a musical instrument such as a bass drum, snare drum, or symbol crash.

Running either in real time or after the fact, Log4JFugue counts the occurrences of each message in one-second time increments and creates a corresponding music stream. As the program runs, you can hear what it’s doing, the pace at which it is running, and the relative frequency of errors. Your brain will soon recognize when the sonic patterns change.