junit-team/junit5 · error · PreconditionViolationException

Could not find any resource(s) with name: ${this.classpathRe

Error message

Could not find any resource(s) with name: ${this.classpathResourceName}

What it means

Thrown by ClasspathResourceSelector.getResources() (line 125-138) when lazy resolution via ResourceSupport.tryToGetResources succeeds but returns an empty set, i.e. no classpath/module-path entry contains a resource with the given name. It is a PreconditionViolationException, distinct from the 'Could not load' variant which fires when the lookup itself fails (line 128-130).

Source

Thrown at junit-platform-engine/src/main/java/org/junit/platform/engine/discovery/ClasspathResourceSelector.java:132

	/**
	 * Get the selected {@link Resource resources}.
	 *
	 * <p>If the {@link Resource resources} were not provided, but only their name,
	 * this method attempts to lazily load the {@link Resource resources} based on
	 * their name and throws a {@link PreconditionViolationException} if the
	 * resource cannot be loaded.
	 *
	 * @since 1.14
	 */
	@API(status = MAINTAINED, since = "1.14")
	public Set<Resource> getResources() {
		if (this.resources == null) {
			Try<Set<Resource>> tryToGetResource = ResourceSupport.tryToGetResources(this.classpathResourceName);
			Set<Resource> classpathResources = tryToGetResource.getNonNullOrThrow( //
				cause -> new PreconditionViolationException( //
					"Could not load resource(s) with name: " + this.classpathResourceName, cause));
			if (classpathResources.isEmpty()) {
				throw new PreconditionViolationException(
					"Could not find any resource(s) with name: " + this.classpathResourceName);
			}
			this.resources = unmodifiableSet(classpathResources);
		}
		return this.resources;
	}

	/**
	 * Get the selected {@code FilePosition} within the classpath resource.
	 */
	public Optional<FilePosition> getPosition() {
		return Optional.ofNullable(this.position);
	}

	/**
	 * @since 1.3
	 */
	@API(status = STABLE, since = "1.3")

View on GitHub (pinned to 956246301e)

Solutions

Confirm the resource exists: getClass().getClassLoader().getResource(name) returns non-null before building the selector.
Drop any leading '/' (the constructor already does, so passing 'com/foo/data.json' directly is correct).
If the resource is in a named module, ensure the containing package is open to the framework (opens/exports) so the resource is resolvable.
Rebuild the project to ensure src/test/resources is copied to the output directory / packaged into the jar under test.

Example fix

// before
var selector = DiscoverySelectors.selectClasspathResource("com/example/data.json");
// ... resources missing on classpath -> throws on resolution

// after
String name = "com/example/data.json";
if (Thread.currentThread().getContextClassLoader().getResource(name) == null) {
    throw new IllegalStateException("resource not on classpath: " + name);
}
var selector = DiscoverySelectors.selectClasspathResource(name);

Defensive patterns

Strategy: validation

Validate before calling

String name = "com/example/data.json";
ClassLoader cl = Thread.currentThread().getContextClassLoader();
boolean exists = cl.getResource(name) != null;
if (!exists) throw new IllegalStateException("resource not on classpath: " + name);
var selector = DiscoverySelectors.selectClasspathResource(name);

Try / catch

try {
    selector.getResources(); // forces lazy resolution
} catch (PreconditionViolationException e) {
    throw new IllegalStateException("classloaders missing the resource", e);
}

Prevention

Confirm getClass().getClassLoader().getResource(name) is non-null before building the selector.
For named modules, ensure the owning package is open to the framework.
Do not prefix the name with a leading slash (the constructor strips one anyway).

When it happens

Trigger: Calling DiscoverySelectors.selectClasspathResource(name) and then getResources()/getClasspathResources() (or letting an engine resolve it) when 'name' does not match any resource resolvable by the context ClassLoader. The constructor strips a leading '/' so a name like '/foo.json' becomes 'foo.json'; mismatches in package-style paths matter.

Common situations: Resource lives in src/test/resources but the test runs with a classpath that omits it (shading/relocating); wrong path separator or case sensitivity on case-sensitive filesystems; resource packaged in a jar that isn't on the classpath; module-path resource not opened/exports correctly; typo in the resource name.

Related errors

AI-assisted analysis of junit-team/junit5@956246301e (2026-08-04). Data as JSON: /data/errors/29d7c44f8bf65efe.json. Report an issue: GitHub.