## 5 Results
### Answers to RQs
#### 5.1.3 RQ3: What Are the Current Challenges in the Management of DSPL? Finding the most relevant challenges will serve to develop a continuous improvement in the development of the DSPL and satisfy the main problems mentioned by the authors. Similar to question RQ1, a change was made concerning the initial classification in the SMS protocol since it was not known what challenges precisely existed in managing the DSPL. Therefore, to answer this research question, the classification will be based on the guidelines proposed by [PERSON] et al. [47], which proposes areas of application of the variability mechanisms. Additionally, a section related to the validations of the proposal, either in different application areas or in industrial systems, was added. * Techniques: While some mechanisms use general techniques supported by almost all programming languages (e.g., cloning, conditional, and module execution), other mechanisms can only be applied in programming languages or even require a specific environment or tool (Aspect Aspect Orientation, Frame Technology). * Open variation: Mechanisms that allow open variability can enable external developers to provide software artifacts that extend the system after compilation while allowing the kernel to be treated as a \"black box\" with additionally defined points of variation. * Explicit variation points: These are mechanisms in which the possible changes it may contain in its variability are explicitly defined. \begin{table}
\begin{tabular}{l l} \hline \hline
**Methodologies Used to Manage** & **Selected Papers** \\
**DSPL Runtime Variability** & \\ \hline \hline Proprietary architecture & SP1, SP4, SP5, SP6, SP7, SP9, SP10, SP11, SP13, SP15, SP17, SP18, SP19, SP20, SP21, SP24, SP26, SP27, SP29, SP31, SP32, SP35, SP37, SP41, SP43, SP44, SP45, SP46, SP48, SP49, SP52, SP54, SP55, SP59, SP60, SP62, SP63, SP64, SP65, SP66, SP67, SP68, SP70, SP71, SP72, SP73, SP74 SP78, SP81, SP83, SP84. \\ \hline MAPE-K control loop & SP2, SP3, SP8, SP23, SP28, SP30, SP33, SP34, SP36, SP39, SP40, SP42, SP50, SP57, SP58, SP61, SP75, SP77, SP79, SP80, SP82. \\ \hline Third-party software & SP12, SP14, SP25, SP69. \\ Agent-Oriented Software Engineering & SP16, SP38, SP47, SP51, SP53, SP56, SP76. \\ No specific methodology & SP22. \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Selected papers and methodologies for managing DSPLs. Figure 6: Methodologies for managing DSPLs. Support of defaults: Seeks to support and mitigate possible errors that runtime variability can generate. For example, [PERSON] mentions that in some cases where the default selection at a variation point can reduce the number of variants (by one) and simplify the variation logic [47]. * Binding time: In the software lifecycle, specific features are instantiated and bound to a variant at a specific time, either at build time (preprocessing and compilation) or run time. Maintaining a mechanism to manage binding times allows variability to be configured in advance and reconfigurations to be optimized. * Variant isolation: The code variants for each point of variation are written in a source file or isolated modules or files, allowing grouping, for example, of backup systems. * Proposal validation: Proposed frameworks to manage variability in execution time, where the methodology must be validated in several areas because they are laboratory tests. * Granularity: Depending on the variability mechanism used, the granularity of variants differs. Some mechanisms are based on textually describing variants or variation points, admitting any granularity in a source file. In contrast, other mechanisms impose a specific size or shape of variants within the code structure (e.g., a function, a class, or a file). * Non-code artifacts: Software systems include several types of artifacts in addition to code, for example, variability modeling, data files, or text files. However, some of the mechanisms presented are applicable only to code. * No challenges mentioned. Twenty-four (28.6%) papers present challenges associated with _Techniques_.