A Conceptual Model for Visualising Concurrent Java Programs Using UML

Understanding concurrent object-oriented software execution is not a trivial task. This is mainly due to the interleaving of threads, and multiple flows of control that result in different outputs being produced at successive executions of the program. We believe that visualisation can be of assistance to developers in expediting the comprehension of concurrent object-oriented software. In this paper, we discuss the issues associated with concurrency and the challenges faced when attempting to display these issues visually. We present Jacot, an environment to exemplify the intricacies of concurrency in Java at run-time. This environment is based on the Unified Modeling Language (UML) paradigm and uses the Java Debug Interface (JDI) for event gathering. The visualisation model also defines extensions to be made to the UML to incorporate concurrency constructs. The originality of this research is its aim at completeness of representation of concurrency issues.