Feature-oriented programming FOP, and aspect-oriented programming AOP have been used to develop modular software product lines SPL. Both approaches focus on modularizing classes behavior and crosscutting concerns CC. Therefore, the symbiosis of FOP and AOP would permit reaching pros and cons of both software development approaches. Concretely, FOP permits a modular refinement of classes collaboration for software product lines SPL -an adequate structural representation of heterogeneous CC, but FOP does not well represent homogeneous CC. On the other hand, traditional AOP structurally well modularizes homogeneous CC, but aspects are not adequate to represent collaboration of classes for software evolution. In addition, AOP solutions present implicit dependencies and strong coupling between classes and aspects. Since Join Point Interface JPI solves mentioned AOP issues, this paper present JPI Feature Modules to represent and modularize the structure of FOP and JPI SPL instances, i.e., classes and join point interfaces for a transparent implementation in a FOP and JPI context. This paper, highlights benefits of a FOP and JPI symbiosis for the modular software conception using a case study to exemplify its use.