jGRASP has three integrated approaches for interacting with its dynamic viewers for data structures: debugger, workbench, and text-based interactions that allow individual Java statements and expressions to be executed/evaluated. These approaches can be used together to provide a complementary set of interactions with the dynamic viewers. Data structure identification and rendering were tested by examining examples from 20 data structure textbooks. Controlled experiments with CS2 students indicate that the viewers can have a significant positive impact on student performance. The overall result is a flexible environment for interacting with effective dynamic data structure visualizations generated by a robust structure identifier.