Live object exploration: Observing and manipulating behavior and state of Java objects

In this paper we introduce a visual representation of Java objects that can be used for observing and manipulating behavior and state of currently developed classes. It runs separately, e.g., on a tablet, beside an integrated development environment. Within the visualization, developers are able to arbitrarily change the object state, then invoke any method with custom parameters and observe how the object state changes. When changing the source code of the related class, the visualization holds the previous object state and adapts the new behavior defined by the underlying source code. This instantly enables developers to observe functionalities objects of a certain class have and how they manipulate their state, and especially, how source code changes influence their behavior. We implemented a first prototype as a touch-enabled web application that is connected to a conventional integrated development environment. In order to gain first practical insights, we evaluated our approach in a pilot user study.