JIVE: A Pedagogic Tool for Visualizing the Execution of Java Programs

The authors describe a pedagogic tool called JIVE (Java Interactive Visualization Environment) for clarifying the dynamic behavior of Java programs. The tool has the following main goals: provide clear visualizations of execution state and call history, with varying levels of granularity; show method calls within object contexts; support declarative queries over executions; and, support forward and reverse stepping. JIVE employs extensions of UML object and sequence diagrams to represent execution state and call history. While these diagrams are normally used as design-time specifications, their use for depicting run-time behavior helps close the gap between design and execution. They illustrate the use of JIVE for understanding typical data structure operations.