OpenClover vs ReportGenerator

OpenClover is a free code coverage tool for Java, Groovy and AspectJ. It tracks global, per-test and distributed per-test coverage using method, statement and branch metrics. More than 20 built-in code metrics are included, and custom metrics are supported. Coverage reports can be generated as HTML, XML, PDF, JSON or text. You can narrow coverage scope by paths, classes, methods, code blocks, statements, complexity or inline comments. For test optimization, OpenClover identifies tests to rerun when classes change, can run failing tests first, and can randomize test order. Integrations include Ant, Maven, Gradle, Grails, Griffon, Jenkins, Bamboo, Eclipse, IntelliJ IDEA, Sonar and JIRA. Dedicated test support covers JUnit 3 and 4, TestNG and Spock. Version 5.1.x supports JRE or JDK 8 through 25 and Groovy 3.x, 4.x and 5.x. The project is volunteer-maintained and Apache 2.0 licensed; community support typically responds within a few days.

ReportGenerator is a command-line tool that turns code coverage reports into readable reports and visualizes covered source lines. It runs on Windows, Linux, and macOS, and accepts input from tools and formats including coverlet, OpenCover, dotCover, Visual Studio, NCover, Cobertura, JaCoCo, Clover, gcov, and lcov. Reports visualize line and branch coverage; method coverage is a PRO feature. A history chart tracks coverage over time, and the summary table can be filtered and sorted. Risk hotspot analysis can use cyclomatic complexity, NPath complexity, and CRAP score when those values are available, with configurable warning thresholds. Output choices include HTML, Clover, Cobertura, OpenCover, SonarQube, lcov, TeamCity summary, XML, Markdown, JSON, CSV, and text. The maker says GitHub Actions and Azure DevOps are supported. The project is open source under the Apache License, with basic features free and additional features requiring PRO. Lifetime licenses cost $79 as a one-time purchase for an individual, $249, paid once for up to 10 developers, or $599, paid once for unlimited developers.