Visually Exploring Object Mutation

Object-oriented programming supports object mutation during a program execution. A mutation occurs whenever a value is assigned to an object field. Analyzing the evolution of object mutation is known to be difficult. Unfortunately, classical code debuggers painfully support the analysis of object mutations. Object Evolution Blueprint is a visualization dedicated to exploring object mutation over time. Our blueprint visually and concisely represents sequences of field mutations. The history of each field is adequately shown with respect to the dynamic value types. We have observed the use of our blueprint with three practitioners. Our visualization has been well received and accepted to complete two different software comprehension tasks. Moreover, our user study shows that the visualization is both intuitive and simple to learn.