junit-team/junit5 · error · JUnitException

OutputDirectoryCreator not available; probably due to unalig

Error message

OutputDirectoryCreator not available; probably due to unaligned versions of the junit-platform-engine and junit-platform-launcher jars on the classpath/module path.

What it means

The default EngineDiscoveryRequest.getOutputDirectoryCreator() method (line 111-114) throws this JUnitException precisely to signal that no implementation supplied an OutputDirectoryCreator. In a normal Launcher setup the launcher overrides this default; hitting it means the junit-platform-launcher jar is absent or its version does not match junit-platform-engine, so the wiring that injects the creator never happens.

Source

Thrown at junit-platform-engine/src/main/java/org/junit/platform/engine/EngineDiscoveryRequest.java:112

	 * @since 1.12
	 * @deprecated Please use {@link #getOutputDirectoryCreator()} instead
	 */
	@SuppressWarnings("removal")
	@Deprecated(since = "1.14", forRemoval = true)
	@API(status = DEPRECATED, since = "1.14")
	default org.junit.platform.engine.reporting.OutputDirectoryProvider getOutputDirectoryProvider() {
		return org.junit.platform.engine.reporting.OutputDirectoryProvider.castOrAdapt(getOutputDirectoryCreator());
	}

	/**
	 * Get the {@link OutputDirectoryCreator} for this request.
	 *
	 * @return the output directory creator; never {@code null}
	 * @since 1.14
	 */
	@API(status = MAINTAINED, since = "1.14")
	default OutputDirectoryCreator getOutputDirectoryCreator() {
		throw new JUnitException(
			"OutputDirectoryCreator not available; probably due to unaligned versions of the junit-platform-engine and junit-platform-launcher jars on the classpath/module path.");
	}

}

View on GitHub (pinned to 956246301e)

Solutions

Align all junit-platform-* artifacts to the same version via the junit-bom in your dependency management.
Ensure junit-platform-launcher is actually on the runtime classpath/module path, not just junit-platform-engine.
If you implement EngineDiscoveryRequest yourself, override getOutputDirectoryCreator() to return a real OutputDirectoryCreator.
Run a dependency tree (gradle dependencies / mvn dependency:tree) to confirm the launcher jar resolves and at the expected version.

Example fix

// before: build.gradle.kts with mismatched versions
implementation("org.junit.platform:junit-platform-engine:1.14")
// launcher missing or older

// after: align via BOM
dependencies {
    implementation(platform("org.junit:junit-bom:6.x"))
    implementation("org.junit.platform:junit-platform-launcher")
    implementation("org.junit.platform:junit-platform-engine")
}

Defensive patterns

Strategy: validation

Validate before calling

OutputDirectoryCreator creator;
try {
    creator = request.getOutputDirectoryCreator();
} catch (JUnitException e) {
    throw new IllegalStateException("Launcher missing or versions unaligned; cannot get OutputDirectoryCreator", e);
}

Try / catch

try {
    return request.getOutputDirectoryCreator();
} catch (JUnitException e) {
    // degrade gracefully or surface a clear 'align your junit-platform-* versions' message
    throw e;
}

Prevention

Use the junit-bom to keep all junit-platform-* artifacts at one version.
Run a dependency tree check in CI to confirm junit-platform-launcher resolves.
If you implement EngineDiscoveryRequest, always override getOutputDirectoryCreator().

When it happens

Trigger: A custom TestEngine or tool calls request.getOutputDirectoryCreator() on a hand-built EngineDiscoveryRequest that did not override the default method. Also triggered when junit-platform-engine is on the classpath but junit-platform-launcher is missing or is an older/newer version that predates the OutputDirectoryCreator API (added in 1.14).

Common situations: Mixing JUnit Platform versions (e.g. engine 1.14+ with launcher 1.13); shading/relocating jars and accidentally dropping the launcher; building a standalone tool that constructs EngineDiscoveryRequest implementations directly; module path setup where the launcher module is not resolved.

Related errors

AI-assisted analysis of junit-team/junit5@956246301e (2026-08-04). Data as JSON: /data/errors/e090050786b39470.json. Report an issue: GitHub.