The Ninja Jukebox

We present the design and implementation of the ``Ninja Jukebox'', an infrastructural service that allows a community of users to build a distributed, collaborative music repository that delivers digital music to Internet clients, and that performs simple collaborative filtering based on users' song preferences inferred by the service. The Jukebox, implemented in Java, was designed to allow rapid service evolution and reconfiguration, simplicity in participation, and extensibility. We demonstrate that our careful use of a distributed component architecture enabled rapid prototyping of the service, and that our use of carefully designed, strongly typed interfaces enabled the smooth evolution of the service from a simple prototype to a more complex, mature system.