JPlag

JPlag is a high-performance, open-source tool specifically engineered for detecting plagiarism and similarity across various programming languages. Unlike standard text-based detectors, JPlag's technical architecture is based on the 'Greedy String Tiling' (GST) algorithm combined with sophisticated tokenization. It translates source code into a stream of tokens, effectively ignoring non-functional changes such as variable renaming, whitespace alterations, or comment modifications. As we move into 2026, JPlag has become a critical asset in the AI-augmented development landscape, serving as a robust mechanism to identify 'Structural Plagiarism'—where AI generators like GitHub Copilot or ChatGPT produce code that mirrors specific protected logical structures. By focusing on the underlying syntax and logic flow rather than surface-level character matching, JPlag remains more resilient to obfuscation techniques than traditional detectors. It supports a wide array of languages including Java, Python, C#, C++, and JavaScript, making it the industry standard for academic institutions and large-scale open-source project audits to ensure code provenance and maintain intellectual property integrity in an era dominated by LLM-generated software.