Robustness is critical for ensuring that software functions correctly under adverse conditions. Exception-handling mechanisms in programming languages enable developers to structure the code that deals with these adverse conditions. However, implementing the exception-related code may present significant challenges to developers. In this context, this paper reports a study in which we investigated the attention given by developers to the exception-related code across Java projects of the Apache ecosystem. We analyzed the exception-related pull requests (exception-PRs), which were detected with a validated heuristic, to characterize and classify the aspects of these contributions. We produced a comprehensive dataset of 986 exception-PRs detected with the proposed heuristic. A tally of 280 PRs was manually analyzed to characterize and classify the aspects of these contributions to the exception-related code. Our results reveal several trends. First, no statistically significant differences are observed in complexity metrics for exception-PRs versus non-exception-PRs. Similarly, no significant differences are observed in developers' behavior metrics, indicating consistent engagement regardless of whether the pull request addressed exceptional code or not. Most exception-PRs focus on system improvements rather than bug fixes, underscoring proactive efforts to enhance software robustness. Moreover, the most frequently addressed aspects of exceptional code in these exception-PRs are: (i) the external representation of the adverse situations to end-users (more than 40% of the PRs), and (ii) the implementation of effective error handling actions (nearly 35% of the PRs) to promote the program recoverability. Interestingly, a significant proportion of exception-PRs addresses simultaneously various of these (and other) aspects.
- Full list of exception-PRs identified by the heuristic in the Druid.
- Full list of exception-PRs identified by the heuristic in the Pulsar.
- Full list of exception-PRs identified by the heuristic in the Flink.
| Exception aspect occurrence | % | # | Bug fix | Improvement | New feature | Test | Other |
|---|---|---|---|---|---|---|---|
| Error representability - External | 42.52% | 108 | 19.44% | 77.77% | 1.85% | 0.92% | 0.00% |
| Error recoverability - Effective error handling | 36.22% | 92 | 48.91% | 46.73% | 2.17% | 1.08% | 1.08% |
| Error detectability | 23.62% | 60 | 40.00% | 56.67% | 0.00% | 3.33% | 0.00% |
| Error representability - Internal | 20.47% | 52 | 36.53% | 63.46% | 0.00% | 0.00% | 0.00% |
| Error recoverability - Program continuity | 20.47% | 52 | 55.76% | 42.30% | 0.00% | 1.92% | 0.00% |
| Other | 19.69% | 50 | 68.00% | 26.00% | 0.00% | 6.00% | 0.00% |
| Error propagartion | 16.54% | 42 | 26.19% | 69.05% | 2.38% | 2.38% | 0.00% |
| Error recoverability - Cleanability | 7.48% | 19 | 36.84% | 63.15% | 0.00% | 0.00% | 0.00% |
| Exception aspect occurrence (combinations) | % | # | Bug fix | Improvement | New feature | Test | Other |
|---|---|---|---|---|---|---|---|
| Error recoverability, Error representability | 12.99% | 33 | 39.39% | 57.58% | 3.03% | 0.00% | 0.00% |
| Error detectability, Error recoverability, Error representability | 7.09% | 18 | 44.44% | 55.56% | 0.00% | 0.00% | 0.00% |
| Error propagartion, Error recoverability, Error representability | 5.51% | 14 | 42.86% | 50.00% | 7.14% | 0.00% | 0.00% |
| Error detectability, Error representability | 4.33% | 11 | 18.18% | 81.82% | 0.00% | 0.00% | 0.00% |
| Error detectability, Error recoverability | 3.94% | 10 | 70.00% | 30.00% | 0.00% | 0.00% | 0.00% |
| Error propagartion, Error representability | 3.94% | 10 | 10.00% | 90.00% | 0.00% | 0.00% | 0.00% |
| Error detectability, Error propagartion, Error recoverability | 1.57% | 4 | 25.00% | 75.00% | 0.00% | 0.00% | 0.00% |
| Error propagartion, Error recoverability | 1.18% | 3 | 33.33% | 66.67% | 0.00% | 0.00% | 0.00% |
| Error detectability, Error propagartion, Error representability | 0.79% | 2 | 0.00% | 100.00% | 0.00% | 0.00% | 0.00% |
| Error recoverability, Other | 0.79% | 2 | 50.00% | 50.00% | 0.00% | 0.00% | 0.00% |
| Error propagartion, Other | 0.39% | 1 | 0.00% | 100.00% | 0.00% | 0.00% | 0.00% |
| Error detectability, Error recoverability, Other | 0.39% | 1 | 100.00% | 0.00% | 0.00% | 0.00% | 0.00% |
| Error propagartion, Error representability, Other | 0.39% | 1 | 0.00% | 100.00% | 0.00% | 0.00% | 0.00% |
| Error representability, Other | 0.39% | 1 | 0.00% | 100.00% | 0.00% | 0.00% | 0.00% |