Context: The development of complex systems of systems leads to high development cost, uncontrollable software quality and low productivity. Thus Component-based software development was used to improve development effort and cost of the software. Heterogeneous systems are the system of systems that consist of functionally independent sub-systems with at least one sub-system exhibiting heterogeneity with respect to other systems. The context of this study is to investigate the usage of third party components in heterogeneous systems.

Objectives. In this study an attempt was made to investigate the usage of third party components in heterogeneous systems in order to accomplish the following objectives:

• Identify different types of third party components.
• Identify challenges faced while integrating third-party components in heterogeneous systems.
• Investigate the difference in test design of various third party components
• Identify what the practitioners learn from various third party components

Methods: We have conducted a systematic literature review by following Systematic literature review guidelines by Kitchenham to identify third party components used, challenges faced while integrating third-party components and test design techniques. Qualitative interviews were conducted in order to complement, supplement the finding from the SLR and further provide guidelines to the practitioners using third party components. The studies obtained from the SLR were analyzed in relation to the quality criteria using narrative analysis. The data obtained from interview results were analyzed using thematic analysis.

Results: 31 primary studies were obtained from the systematic literature review (SLR).  3 types of third components, 12 challenges, 6 test design techniques were identified from SLR.  From the analysis of interviews, it was observed that a total of 21 challenges were identified which complemented the SLR results. In addition, from interview test design techniques used for testing of heterogeneous systems having third party components were investigated. Interviews have also provided 10 Recommendations for the practitioners using different types of third party components in the product development.

Conclusions: To conclude, commercial of the shelf systems (COTS and Open software systems (OSS) were the third party components mainly used in heterogeneous systems rather than in-house software from the interview and SLR results. 21 challenges were identified from SLR and interview results. The test design for testing of heterogeneous systems having different third party components vary, Due to the non-availability of source code, dependencies of the subsystems and competence of the component. From the analysis of obtained results, the author has also proposed guidelines to the practitioners based on the type of third party components used for product development.