# JUnit Examples for Jupiter, Vintage, and Platform Setups

> JUnit Examples is a repository of Java example applications and extensions for learning and testing JUnit configurations across Ant, Gradle, Maven, Bazel, and sbt. It is most useful as a reference for setup choices, custom extensions, engine integration, and migration work, rather than as a production test framework.

**junit-team/junit-examples** — Collection of JUnit example projects

- Repository: https://github.com/junit-team/junit-examples
- Website: https://junit.org
- Stars: 1,620 · Forks: 1,378
- Language: Java
- License: EPL-2.0
- Published: 2026-10-16 · Updated: 2026-10-16 · Language: en
- Canonical page: https://hysenlabs.com/projects/junit-team-junit-examples

## What junit-examples Provides

junit-team/junit-examples is a collection of example applications and extensions built around JUnit Jupiter, JUnit Vintage, and the JUnit Platform. The intended audience is Java developers who need a concrete reference for configuring JUnit or understanding how its pieces fit together. The repository is not one continuous application. Instead, the top-level layout exposes separate directories for starter projects, migration examples, extension examples, and Platform samples. That distinction matters when deciding how to use it. A developer looking for the smallest Gradle setup can inspect one directory, while a developer migrating older tests can compare dedicated Maven and Gradle examples without treating those configurations as interchangeable. The README identifies starter examples for Ant, Gradle, Gradle with Kotlin and Groovy, Maven, Maven with Kotlin, Bazel, and sbt. It also identifies examples for custom JUnit Jupiter extensions, migration from JUnit 3 or JUnit 4 based projects, multiple test engines, and modular code. The collection is therefore useful for narrowing a configuration decision before adapting code in a separate project. The repository is not archived. Its last push was on 2026-10-14, although it has no GitHub releases, so version pinning should be based on the checked-out repository state and its build files rather than release tags.

## How the Examples Are Organized

The repository uses one directory per scenario, with each directory representing a complete example project rather than a shared library that applications import. The starter directories cover build-system and language combinations, which allows a developer to compare the same general JUnit subject across different project generators. The migration directories combine the JUnit Platform, Jupiter, and Vintage components, matching the migration scenario described in the README. The junit-jupiter-extensions directory focuses on the Jupiter Extension API, while junit-multiple-engines focuses on a Gradle project using several TestEngine implementations. The junit-modular-world example adds Java Platform Module System concerns and a custom TestEngine for the JUnit Platform. Based on this layout, the examples appear to be intended as inspectable build configurations. The README does not document a central runtime service, a shared plugin, or an API that callers should depend on. It does document continuous integration through GitHub Actions for building the example projects. That makes the repository useful as a set of maintained references, but it also means adoption usually involves selecting one directory and translating its dependencies and scripts into the target project. The source launcher entry in src/Builder.java provides a repository-wide build entry point for the examples when the required Java runtime is available.

## Building the Collection with the Java Source Launcher

The README gives one repository-level build command for JDK 24 or later. The command uses Java's multi-file source-code launcher feature, so it does not require the reader to infer a Gradle or Maven wrapper invocation for the collection as a whole. Run it from the main directory of the repository. The repository does not describe the generated output, so the result to expect is the README's stated outcome: the example projects are built. Individual examples still have their own build-system directories, and the collection-wide command should not be confused with a normal application startup command. The command is especially relevant when comparing the examples or checking the repository's CI path. It does not replace opening a specific example to understand its configuration.

## Starting with a Jupiter Build-System Example

There is no single install command in the README for one selected build tool because each example directory represents a separate project. The collection-level Java source launcher is the documented build entry point, while the starter directories provide the configurations to inspect. For example, the repository includes junit-jupiter-starter-gradle, junit-jupiter-starter-maven, junit-jupiter-starter-ant, junit-jupiter-starter-bazel, and junit-jupiter-starter-sbt. The README describes the Gradle and Maven examples as bare minimum setups, which makes them sensible starting points for a developer learning JUnit Jupiter. A practical first use is to open the chosen directory, inspect its build configuration and test sources, then use that build tool's normal local commands. The README does not give exact commands for running one individual example, and the repository listing alone does not establish whether each directory includes a wrapper or which command syntax applies. The documented repository-wide command remains the only build command copied from the README. The choice of example should match the build system already used by the target project. A Maven developer should begin with the Maven starter, while a Gradle developer should begin with the Gradle starter.

## Extensions, Engines, and Modular Testing

The more specialized examples address JUnit mechanisms beyond a basic test setup. The junit-jupiter-extensions example is described as a demonstration of implementing custom JUnit Jupiter extensions and using them in tests. This is the clearest project-specific case for studying behavior that belongs outside ordinary test methods, although the README does not document extension lifecycle details or list the included extension names. The junit-multiple-engines example configures a Gradle project with various JUnit Platform TestEngine implementations. Its value is comparative: it places multiple engines in one Platform setup instead of presenting Jupiter as the only execution model. The junit-modular-world example focuses on code organized in modules and also demonstrates a custom TestEngine using the Java Platform Module System. That sample is more specialized than a starter project and carries additional constraints from module boundaries. The repository does not claim that these examples are interchangeable with ordinary Maven or Gradle projects. They are better treated as focused demonstrations. If the goal is only to run basic Jupiter tests, the starter examples are the direct fit. If the goal is to write an extension, compose engines, or test modular code, the specialized directory provides a more relevant starting point.

## Migration Examples and Their Boundaries

The migration section contains junit-migration-gradle and junit-migration-maven. According to the README, both configure the JUnit Platform, Jupiter, and Vintage, providing a possible migration path for projects based on JUnit 3 or JUnit 4. This distinction is important because a migration example is not simply a newer starter project. Vintage is included specifically to represent older test execution during the transition, while Jupiter covers the newer programming model. The README does not claim that either example performs an automatic source-code migration, identifies a complete list of legacy annotations, or documents a rollback procedure. Consequently, developers should treat these directories as configuration references for assembling a mixed test setup, not as a turnkey converter. Build-system choice also remains visible in the project structure. The Gradle and Maven examples may solve a similar migration problem through different build files, and the repository does not state that their dependency graphs or execution details are identical. A team should compare the relevant migration directory with the existing build setup before copying it.

## Licensing, Maintenance, and Adoption Cost

The repository is identified under the EPL-2.0 license. That designation matters for organizations reviewing the terms under which they copy or adapt example code, but it is not a legal opinion about a particular deployment. The repository is not archived, and the last push was on 2026-10-14. It has no GitHub releases, so there is no release-based upgrade stream documented here. The practical maintenance cost comes from reviewing the example directory as a configuration reference and keeping its dependencies aligned with the JUnit and build-tool versions used by the consuming project. There is no documented service migration or runtime state to operate. The repository-wide CI workflow is relevant because it builds example projects, but the README does not specify individual dependency upgrade procedures. The absence of GitHub releases also means that a checkout date or commit is a more concrete maintenance reference than a release number. This lowers the amount of production infrastructure required, while increasing the need to inspect configuration details before adoption.

## Conclusion

Adopt this repository when you need a concrete JUnit setup or migration example, especially when choosing between build systems or examining extension and engine configuration. Do not treat it as a reusable test framework or assume that one example matches every project. Verify the selected example's build files, JDK requirements, engine choices, and compatibility with your application before copying its configuration.

## FAQ

### What does junit-team/junit-examples contain?

It contains separate example applications and extensions for JUnit Jupiter, JUnit Vintage, and the JUnit Platform. The examples cover starter setups, extensions, migrations, multiple engines, and modular code.

### How do I build all the JUnit examples?

The README says to run `java src/Builder.java` from the main directory using JDK 24 or later. It says this uses Java's multi-file source-code launcher feature to build all examples.

### Which example should I use for JUnit migration?

The repository includes `junit-migration-gradle` and `junit-migration-maven`. Both are described as configuring the JUnit Platform, Jupiter, and Vintage for a possible migration path from JUnit 3 or JUnit 4 based projects.

## Sources

- [Issues](https://github.com/junit-team/junit-examples/issues)
- [junit-team/junit-examples on GitHub](https://github.com/junit-team/junit-examples)
- [License: EPL-2.0](https://github.com/junit-team/junit-examples/blob/main/LICENSE)
- [Project website](https://junit.org)
- [README](https://github.com/junit-team/junit-examples/blob/main/README.md)

---

Hysen Labs editorial analysis, written from the project's own repository and release notes. Cite the canonical page: https://hysenlabs.com/projects/junit-team-junit-examples