In vivo test and rollback of Java applications as they are

Summary Modern software systems accommodate complex configurations and execution conditions that depend on the environment where the software is run. While in house testing can exercise only a fraction of such execution contexts, in vivo testing can take advantage of the execution state observed in the field to conduct further testing activities. In this paper, we present the Groucho approach to in vivo testing. Groucho can suspend the execution, run some in vivo tests, rollback the side effects introduced by such tests, and eventually resume normal execution. The approach can be transparently applied to the original application, even if only available as compiled code, and it is fully automated. Our empirical studies of the performance overhead introduced by Groucho under various configurations showed that this may be kept to a negligible level by activating in vivo testing with low probability. Our empirical studies about the effectiveness of the approach confirm previous findings on the existence of faults that are unlikely exposed in house and become easy to expose in the field. Moreover, we include the first study to quantify the coverage increase gained when in vivo testing is added to complement in house testing.