Experimental evaluation of animated-verifying object viewers for Java

Although many visualization techniques have been shown to be pedagogically effective, they are still not widely adopted. The reasons include: lack of suitable methods of automatic-generation of visualizations, lack of integration among visualizations, and lack of integration with basic integrated development environment (IDE) support. To effectively use visualizations when developing code, it is useful to automatically generate multiple synchronized views without leaving the IDE. The jGRASP IDE provides object viewers that automatically generate dynamic, state-based visualizations of objects and primitive variables in Java. Such seamless integration of a lightweight IDE with a set of pedagogically effective software visualizations is unique and is currently unavailable in any other environment. Multiple instructors have reported positive anecdotal evidence of their usefulness. We conducted formal, repeatable experiments to investigate the effect of these viewers for singly linked lists on student performance and we found a statistically significant improvement over traditional methods of visual debugging that use break-points.