Exception Flows Made Explicit: An Exploratory Study

Most of the exceptions exert a global design impact as they tend to flow through multiple module interfaces of a software system. Exception handling mechanisms in programming languages were originally proposed to improve the robustness and comprehension of error handling code. These mechanisms are traditionally based on the fundamental assumption that global exception flows should be always implicit. However, it has been empirically found that the implementation of global exception handling in real-life software projects tends to exhibit poor quality. This paper presents an exploratory study to assess the benefits and drawbacks of explicit exception flows (or exception channels), as opposed to implicit exception flows. The experiment design involved 15 participants using three alternative mechanisms for exception handling. Our analysis was driven by key indicators of software usability: (i) implementation time, (ii) number of uncaught exceptions, and (iii) number of incorrect answers by the participants.