quarkusio/quarkus · error · DefinitionException

More than 1 parameter of type BeanInfo or ObserverInfo for m

Error message

More than 1 parameter of type BeanInfo or ObserverInfo for method " + method

What it means

Each build-time @Registration extension method may declare only one query parameter — a single BeanInfo or ObserverInfo identifying the target of the registration. ExtensionPhaseRegistration.runExtensionMethod() throws DefinitionException when more than one such parameter is present, since a method registers exactly one bean or observer per invocation.

Source

Thrown at independent-projects/arc/processor/src/main/java/io/quarkus/arc/processor/bcextensions/ExtensionPhaseRegistration.java:56

        int numQueryParameters = 0;
        List<ExtensionMethodParameter> parameters = new ArrayList<>(method.parametersCount());
        for (org.jboss.jandex.Type parameterType : method.parameterTypes()) {
            ExtensionMethodParameter parameter = ExtensionMethodParameter.of(parameterType);
            parameters.add(parameter);

            if (parameter.isQuery()) {
                numQueryParameters++;
            }

            parameter.verifyAvailable(ExtensionPhase.REGISTRATION, method);
        }

        if (numQueryParameters == 0) {
            throw new DefinitionException("No parameter of type BeanInfo or ObserverInfo for method " + method);
        }

        if (numQueryParameters > 1) {
            throw new DefinitionException("More than 1 parameter of type BeanInfo or ObserverInfo for method " + method);
        }

        ExtensionMethodParameter query = parameters.stream()
                .filter(ExtensionMethodParameter::isQuery)
                .findAny()
                .get(); // guaranteed to be there

        List<?> allValuesForQueryParameter = Collections.emptyList();
        if (query == ExtensionMethodParameter.BEAN_INFO) {
            allValuesForQueryParameter = matchingBeans(method.jandex, false);
        } else if (query == ExtensionMethodParameter.INTERCEPTOR_INFO) {
            allValuesForQueryParameter = matchingBeans(method.jandex, true);
        } else if (query == ExtensionMethodParameter.OBSERVER_INFO) {
            allValuesForQueryParameter = matchingObservers(method.jandex);
        }

        for (Object queryParameterValue : allValuesForQueryParameter) {
            List<Object> arguments = new ArrayList<>();

View on GitHub (pinned to e1c734241f)

Solutions

Keep exactly one BeanInfo or ObserverInfo parameter and remove the other.
Split into two @Registration methods — one for the bean, one for the observer.
If you need related metadata, derive it from the single query parameter rather than adding extra info parameters.

Example fix

// before
@Registration
void register(BeanInfo bean, ObserverInfo observer) { ... }

// after
@Registration
void registerBean(BeanInfo bean) { ... }

@Registration
void registerObserver(ObserverInfo observer) { ... }

Defensive patterns

Strategy: validation

Validate before calling

long targets = Arrays.stream(method.getParameters())
    .map(p -> p.type().name().withoutPackagePrefix())
    .filter(n -> n.equals("BeanInfo") || n.equals("ObserverInfo"))
    .count();
if (targets > 1) throw new IllegalStateException("@Registration method must take exactly one BeanInfo or ObserverInfo");

Type guard

static boolean isSingleTargetRegistration(MethodInfo m) {
    return Arrays.stream(m.parameters()).filter(p ->
        Set.of("BeanInfo","ObserverInfo").contains(p.type().name().withoutPackagePrefix())).count() == 1;
}

Try / catch

try {
    processor.run(extensionClass);
} catch (DefinitionException e) {
    fail("Multiple registration targets: " + e.getMessage());
}

Prevention

One registration target per @Registration method; use separate methods for beans vs observers.
Derive related metadata from the single target parameter.
Review extension signatures against the 'exactly one query parameter' rule.

When it happens

Trigger: Declaring an @Registration method with both a BeanInfo and an ObserverInfo parameter (or two BeanInfo parameters), making numQueryParameters > 1 when Arc processes the extension.

Common situations: Trying to register a bean and its observer in a single callback; adding an extra BeanInfo parameter hoping to see related beans; copy-paste from a synthesis-phase method with different rules.

Related errors

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/5dd93dde6bcae80d. Report an issue: GitHub.