OpenClover

OpenClover is a code coverage tool for Java, Groovy and AspectJ projects. It suits teams that want detailed coverage analysis integrated with builds and tests. It is a capable no-cost choice, but Groovy users should account for its IDE integration gap.

Overview

OpenClover measures global, per-test and distributed per-test coverage, with method, statement and branch metrics. Historical trends and coverage gates help teams monitor results over time and apply coverage criteria. More than 20 built-in code metrics, alongside support for custom metrics, add ways to examine code beyond which lines tests exercise.

Its scope filters range from paths and classes to methods, code blocks, statements, complexity and inline comments. That granularity is useful when teams need to focus analysis on selected code; it is more than a minimal coverage utility requires. OpenClover has been free and open-source since 2017 under the Apache 2.0 license, and is maintained by volunteers.

For more options, see our Test Coverage Tools directory.

Key features

Build, test and reporting workflows

Integrations include Ant, Maven, Gradle, Grails and Griffon, plus Jenkins, Bamboo, Eclipse, IntelliJ IDEA, Sonar and JIRA. Dedicated test support covers JUnit 3 and 4, TestNG and Spock. This breadth suits projects that want coverage within established build, CI, IDE and issue-tracking workflows. The important exception is Groovy: it is not supported in the Eclipse or IntelliJ IDEA integrations.

Reports can be generated as HTML, XML, PDF, JSON or TEXT, so teams can choose a format suited to reading or downstream processing. OpenClover can identify tests to rerun after classes change, run failing tests first, or randomize test order. Those options make it relevant not only for reporting coverage but also for shaping test runs.

Pricing

OpenClover — free, billed forever

The single plan has no license tiers, license keys or usage limits. It includes the same coverage, metrics, integrations and test-selection capabilities described above without a paid tier to unlock. There are no seat, quota or trial constraints attached to the plan. Teams should weigh the zero license cost against volunteer maintenance and community support, which typically responds within a few days through documentation, forums and the issue tracker.

Platforms

OpenClover supports Windows, Linux and Apple Mac OS X. The directory categorizes it for Linux, macOS, web and Windows. Version 5.1.x supports JRE or JDK 8 through 25 and Groovy 3.x, 4.x and 5.x, giving Java and Groovy projects a defined runtime range to consider.

Who it's for

OpenClover is a strong fit for Java, Groovy and AspectJ teams that value per-test coverage, detailed filtering, multiple report formats and test-selection controls, especially when their builds already use its supported tools. It is less suitable for teams that require Groovy support inside Eclipse or IntelliJ IDEA, or that need a different language ecosystem. Volunteer maintenance and community-based support may also be a drawback for organizations that require a formal support arrangement.

Pros and cons

• Pros: No usage limits or license tiers, making the tool available without a usage-based ceiling.
• Pros: Global, per-test and distributed coverage, historical trends and coverage gates provide several ways to assess and track test coverage.
• Pros: Test-selection controls and integrations across build, CI, IDE and issue-tracking tools can fit into existing workflows.
• Cons: Groovy is unsupported in the Eclipse and IntelliJ IDEA integrations, limiting IDE workflows for those projects.
• Cons: Support is community-based and the project is volunteer-maintained, rather than backed by a stated formal support offering.

Alternatives

Choose Coveralls if you need a freemium option that states it is always free for open-source and public repositories. ReportGenerator is another freemium alternative, with a free tier described as basic features for open source and paid Individual pricing. For Ruby projects, SimpleCov is a free, MIT-licensed code coverage option. Coverage.py is the free, open-source option among these alternatives for Python coverage.

Microsoft Code Coverage is a free alternative. Coverlet is a free, MIT-licensed option for modern .NET SDK-style projects. gofmt is a free command-line tool included with Go installations. Codecov is a freemium alternative with a free Developer plan.

Verdict

Choose OpenClover if you work in Java, Groovy or AspectJ and want detailed coverage, flexible reports and test-selection features without license or usage limits. Its integrations and metric depth are compelling for teams that need more than a basic coverage summary. Look elsewhere if Groovy IDE integration is essential, or if volunteer maintenance and community support do not meet your needs.