Section: New Results

Automatic Analysis and Repair of Exception Bugs for Java Programs

In 2015, we obtained new results in the field of automated software repair, that is a new and emerging domain of software engineering. The goal of automatic repair is to increase the quality of software systems by automatizing tasks related to fixing of defects and bugs. The new results that we bring are related with the management of runtime exceptions. These results contribute to our objective on self-healing software systems (see Section  3.2 ) and are part of the PhD thesis by Benoit Cornu [11] , defended on 26 November 2015. To improve the available information about exceptions, we have presented a characterization of the exceptions (expected or not, anticipated or not), and of their corresponding resilience mechanisms [16] . We have provided definitions about what is a bug when facing exceptions and what are the already-in-place corresponding resilience mechanisms. We have formalized two formal resilience properties: source-independence and pure-resilience as well as an algorithm to verify them. Then, we have presented two dynamic analysis techniques based on code transformation for analyzing exceptions. Casper is an approach to make bug fixing easier by providing information about the origin of null pointer dereferences. NpeFix is a system to tolerate null pointer dereferences. Both systems are empirically validated on real-world null dereference bugs from large-scale open-source projects