Assessing the Evolution of Quality in Java Libraries

Libraries are increasingly employed in software practice to speed up the development process by reusing available and tested components. Software systems, that are available as libraries, are expected to be well-designed, because they have to adhere to specific principles, in order to accommodate the needs of multiple clients in a robust and stable way. Considering that most software libraries are continuously upgraded, in this paper we investigate the evolution of their quality over time. In particular, we perform a systematic case study to assess whether quality, in terms of three software metrics (CBO, LCOM, WMC), exhibits clear trends during the history of twenty analyzed libraries. The findings indicate that the examined software libraries can be considered as stable software projects in terms of quality, in the sense that in contrast to the general belief about software aging, their quality does not degrade over time.