Maintainability Index Evaluation for Open-Source Java Projects

Abstract

Maintainability index evaluation is important for open-source Java projects because these projects often involve frequent code contributions, evolving dependencies, multiple maintainers, and continuous feature updates. Java projects may develop complexity through large classes, deeply nested methods, high coupling, duplicated logic, and inconsistent coding practices, which can reduce readability and increase maintenance effort. Traditional quality assessment may depend on issue reports or reviewer judgment, but these methods may not provide a measurable view of code maintainability. This article focuses on maintainability index evaluation for open-source Java projects by examining code complexity, lines of code, comment density, module structure, and object-oriented design characteristics. The study discusses how maintainability index values can help identify difficult-to-maintain classes, support refactoring decisions, compare project quality, and monitor code degradation over time. The article concludes that maintainability index evaluation provides a practical metric-based approach for improving code quality, supporting contributor decisions, and strengthening long-term sustainability in open-source Java development.