Increased popularity of open source software (OSS) has led to a considerable proliferation of alternative software. However, there is a lack of studies in literature that shed light into the evaluation of OSS by organizations. In this article, a method to evaluate reliability and maintainability of OSS by using both code-based and community-based aspects is proposed through the synthesis of existing studies in literature. To perform code-based evaluation, some internal attributes of the most recent quality model, ISO/IEC 25010, are selected and object-oriented C&K metrics are employed in an attempt to measure these attributes. To perform community-based evaluation, metrics derived from historical data such as e-mailing lists, problem reports, frequently asked questions, and etc. are utilized to identify and satisfy information needs as conformant to ISO/IEC 15939 standard for software measurement process. The two-dimensional method was used in selection of the Java build tools written in Java, and the results obtained by applying the proposed method and the results obtained by using OSMM and OpenBRR which are common methods in the literature were compared. According to the evaluation and comparison results, the results obtained with the existing models confirm each other and the results obtained with the proposed method.