junit-team/junit5 · error · PreconditionViolationException

Configuration error: <error>.

Error message

Configuration error: <error>.

What it means

Thrown by ResolverFacade.configurationErrorOrSuccess() when exactly one validation error is found during @ParameterizedClass field declaration validation or lifecycle method parameter validation. The errors include: duplicate @Parameter indices, negative @Parameter indices, final @Parameter fields, missing sequential indices, or incompatible lifecycle method parameters. The single error is wrapped as 'Configuration error: <error>.'

Source

Thrown at junit-jupiter-params/src/main/java/org/junit/jupiter/params/ResolverFacade.java:386

					parameterName(actualDeclaration), parameterIndex));
			}
			else if (errors.isEmpty()) {
				parameterDeclarationMapping.put(actualDeclaration, originalDeclaration);
			}
		}
		return errors;
	}

	private static String parameterName(ParameterDeclaration actualDeclaration) {
		return actualDeclaration.getParameterName().map(name -> " '" + name + "'").orElse("");
	}

	private static <T> T configurationErrorOrSuccess(List<String> errors, Supplier<T> successfulResult) {
		if (errors.isEmpty()) {
			return successfulResult.get();
		}
		else if (errors.size() == 1) {
			throw new PreconditionViolationException("Configuration error: " + errors.get(0) + ".");
		}
		else {
			throw new PreconditionViolationException("%d configuration errors:%n%s".formatted(errors.size(),
				errors.stream().collect(joining(lineSeparator() + "- ", "- ", ""))));
		}
	}

	private static void validateIndexedParameters(
			NavigableMap<Integer, List<FieldParameterDeclaration>> indexedParameters, List<String> errors) {

		if (indexedParameters.isEmpty()) {
			return;
		}

		indexedParameters.forEach(
			(index, declarations) -> validateIndexedParameterDeclarations(index, declarations, errors));

		for (int index = 0; index <= indexedParameters.lastKey(); index++) {

View on GitHub (pinned to 956246301e)

Solutions

1. Read the specific error message after 'Configuration error:' — it identifies the exact field and problem
2. Make @Parameter fields non-final (remove final keyword or Lombok val/final annotations)
3. Ensure @Parameter indices are sequential starting from 0 with no gaps
4. Ensure lifecycle methods (@BeforeEach, @AfterEach, etc.) parameter types match the @ParameterizedClass constructor or field types

Example fix

// before
@ParameterizedClass
@CsvSource("1, 2")
class MyTest {
    @Parameter(0) final int a; // final is not allowed
    @Parameter(1) int b;
    MyTest() { }
}

// after
@ParameterizedClass
@CsvSource("1, 2")
class MyTest {
    @Parameter(0) int a; // remove final
    @Parameter(1) int b;
    MyTest() { }
}

// Validate @Parameter field declarations at setup time:
static void validateParameterFields(Class<?> testClass) {
    Set<Integer> indices = new HashSet<>();
    for (Field f : testClass.getDeclaredFields()) {
        Parameter p = f.getAnnotation(Parameter.class);
        if (p == null) continue;
        if (Modifier.isFinal(f.getModifiers()))
            throw new IllegalStateException("@Parameter field " + f + " must not be final");
        if (!indices.add(p.value()))
            throw new IllegalStateException("Duplicate @Parameter(" + p.value() + ")");
    }
}

When it happens

Trigger: Exactly one misconfiguration in a @ParameterizedClass using @Parameter fields: a @Parameter field declared final, two fields with the same @Parameter(index), a @Parameter(-1) on a non-aggregator, a gap in @Parameter indices (e.g., @Parameter(0) and @Parameter(2) with no @Parameter(1)), or a single lifecycle method parameter incompatibility.

Common situations: Declaring @Parameter fields as final (common when using Lombok or records). Skipping an index in a sequence of @Parameter fields. An @AfterEach/@BeforeEach method in a @ParameterizedClass declaring a parameter type incompatible with the class parameter.

Related errors

• %d configuration errors:%n%s
• Constructor injection is not supported for @ParameterizedCla
• Failed to inject parameter value into field: <field>
• Configuration error: You must configure at least one set of
• The display name pattern defined for the parameterized test

AI-assisted analysis of junit-team/junit5@956246301e (2026-08-04). Data as JSON: /data/errors/10ecadcb6bbc818a.json. Report an issue: GitHub.