Java test coverage

Ask your coding agent to set up Supercov in your project:

Install Supercov with brew install supercorp-ai/tap/supercov, or take the
platform archive from the GitHub release. Read supercov docs and check the
supported JDK before running our existing Maven or Gradle tests. Show the
coverage report and any measurement limits. Don't change application code or
tests.

Run it yourself

Java support requires a JDK 17 or newer with Maven or Gradle. Java and Kotlin have no package registry of their own here, so a JVM project takes the binary directly:

brew install supercorp-ai/tap/supercov
supercov --version

npx supercov works where Node.js is already present, and the platform archives on the latest release carry the same build at the same version.

Run your tests

From your project root:

supercov -- mvn test
supercov -- ./gradlew test

Keep the flags your build normally uses. Supercov drives Maven and Gradle as your test command rather than as a plugin: it adds the JUnit Platform launcher it needs to the build file inside its own isolated workspace copy, so your pom.xml and build.gradle are never edited.

Supercov measures every JUnit Platform engine — JUnit 5, JUnit 4 through Vintage, Kotest and Spock — as well as TestNG.

Inspect the run:

supercov runs latest
supercov runs latest gaps --limit 5

Check what the tests assert

Line coverage tells you a statement ran. It does not tell you that a test checked the result. Supercov can ask Jev whether each test would fail if a statement it ran changed. runs latest assertions assess saves the answers (it needs TYPESAFE_API_KEY), and runs latest assertions then lists the statements no test checks, file by file. A statement that is not asserted runs in some test, but nothing that test checks depends on it. See Assertion coverage.

JVM-specific limits

Supercov measures the classes your build compiles for the test run. Generated sources are measured only when the build includes them. See runner support for the detail available from each engine and its measurement limits.

Already using JaCoCo or OpenClover? See how the reports differ. supercov docs coverage-model prints the guide for your installed version.