A set of classes for reactive programming in Java. SugarCubes is a set of Java classes for implementing: event based systems, especially those where events are instantly broadcast throughout the system. Communicating in this framework is like in radio transmissions, where emitters send information that is instantaneously received by all receivers. concurrent systems, in particular thread-less ones. Here, parallelism is a logical programming construct to implement activities which are supposed to proceed concurrently, and not one after the other. reactive systems, which continuously react to activations.