Exception Handling Defects: An Empirical Study

Exception handling mechanisms are a feature common in many programming languages. Improper handling of exceptions can cause failures in software systems. This is especially critical for high-assurance systems where software failures may have severe consequences. Understanding the impact of misusing exception handling is important for better utilization of these constructs. This paper presents an exploratory study to determine whether using exception handling is relatively risky by analyzing the defect densities of exception handling code and the overall source code. Also, statistics representing the prevalence of exception handling code are proposed. The study was conducted with six major Eclipse releases. Essential data was collected using custom scripts to extract exception handling information from the source code and exception handling defects information from bug reports. We found that the density of defects that are closely related to exception handling constructs is relatively high compared to the overall defect density. This implies a relationship between the use of exception handling constructs and the risk of defects. Further studies should be conducted to better determine proper ways to implement exception handling and the root causes of exception defects in the software systems.