Comparitive Study of Variability Management in Software Product Lines and Runtime Adaptable Systems Vander Alves, Daniel Schneider, Martin Becker Fraunhofer IESE Fraunhofer Platz 1, 67663 Kaiserslautern, Germany <first name>.<last name>@iese.fraunhofer.de Nelly Bencomo, Paul Grace Computing department, InfoLab21, Lancaster University, Lancaster, LA1 4WA, United Kingdom {nelly, gracep}@comp.lancs.ac.uk Abstract Software Product Lines (SPL) and Runtime Adaptation (RTA) have traditionally been distinct research areas ad- dressing different problems and with different communities. Despite the differences, there are also underlying common- alities with synergies that are worth investigating in both domains, potentially leading to more systematic variability support in both domains. Accordingly, this paper analyses commonality and differences of variability management be- tween SPL and RTA and presents an initial discussion and our perspective on the feasibility of integrating variability management in both areas. 1. Introduction Software Product Line (SPL) [15] and Runtime Adap- tation (RTA) [35] have traditionally been distinct research areas addressing different problems and with different com- munities (e.g., SPLC and ICSR in the former area and Mid- dleware in the latter). SPL deals with strategic reuse of software artifacts in a specific domain so that shorter time- to-market, lower costs, and higher quality are achieved. In contrast to that, RTA aims for optimized service pro- visioning, guaranteed properties, and failure compensation in dynamic environments. To this end, RTA deals mostly with dynamic flexibility so that structure and behaviour is changed in order to dynamically adapt to changing condi- tions at runtime. Despite the differences, there are also underlying com- monalities with synergies that are worth investigating across both domains. For instance, in terms of commonalities, both areas deal with adaptation of software artifacts: by employing some variability mechanism applied at a specific binding time, a given variant is instantiated for a particular context. Accordingly, the research community has recently begun to explore the synergies between these two research areas. On the one hand, motivated by the need of producing software capable of adapting to fluctuations in user needs and evolving resource constraints [27], SPL researchers have started to investigate how to move the binding time of variability towards runtime [4, 11, 33], also noticeable in the research community with even specific venues, such as the Dynamic Software Product Line (DSPL) workshop at SPLC, currently in its second edition. On the other hand, motivated by the need of more consolidated meth- ods to systematically address runtime variability, RTA re- searchers have started to investigate leveraging SPL tech- niques [24, 14, 10]. Nevertheless, in either case, a refined and systematic comparison between these two areas is still missing. Such comparison could help to explore their synergy with cross- fertilization that could lead to more systematic variability support in both domains. In this context, this paper presents two key contributions: • it analyses commonality and differences of variabil- ity management between SPL and RTA. We define variability management as the handling of variant and common artifacts during software lifecycle including development for and with reuse. We choose variability management because we see it as the common denom- inator for exploring synergies between SPL and RTA; • it presents an initial discussion and our perspective on