quarkusio/quarkus · error · DefinitionException

Declaring class of a managed bean is generic, its scope must

Error message

Declaring class of a managed bean is generic, its scope must be @Dependent: ${beanClass}

What it means

A managed bean whose declaring class is generic (declares type parameters) can only be instantiated with properly resolvable type arguments under @Dependent scope. Any other scope requires proxying, which cannot work with unresolved type variables, so ArC throws a DefinitionException.

Source

Thrown at independent-projects/arc/processor/src/main/java/io/quarkus/arc/processor/Beans.java:1401

            // 2. Stereotype scope
            // 3. Bean defining annotation default scope
            ScopeInfo scope;
            if (scopes.isEmpty()) {
                // Inheritance of type-level metadata: "A scope type explicitly declared by X and inherited by Y from X takes precedence over default scopes of stereotypes declared or inherited by Y."
                scope = inheritScope(beanClass, beanDeployment);
                if (scope == null) {
                    scope = initStereotypeScope(stereotypes, beanClass, beanDeployment);
                    if (scope == null) {
                        scope = initBeanDefiningAnnotationScope(beanDefiningAnnotationScopes, beanClass);
                    }
                }
            } else {
                scope = scopes.get(0);
            }
            if (scope != null // `null` is just like `@Dependent`
                    && !BuiltinScope.DEPENDENT.is(scope)
                    && !beanClass.typeParameters().isEmpty()) {
                throw new DefinitionException(
                        "Declaring class of a managed bean is generic, its scope must be @Dependent: " + beanClass);
            }
            if (!isAlternative) {
                isAlternative = initStereotypeAlternative(stereotypes, beanDeployment);
            }
            if (name == null) {
                name = initStereotypeName(stereotypes, beanClass, beanDeployment);
            }

            if (isAlternative) {
                priority = initAlternativePriority(beanClass, priority, stereotypes, beanDeployment);
                if (priority == null) {
                    // after all attempts, priority is still null, bean will be ignored
                    LOGGER.debugf(
                            "Ignoring bean defined via %s - declared as an @Alternative but not selected by @Priority or quarkus.arc.selected-alternatives",
                            beanClass.name());
                    return null;
                }

View on GitHub (pinned to e1c734241f)

Solutions

1. Make the bean class @Dependent (or remove the scope annotation)
2. Remove the type parameters by making the class concrete with specific types
3. Introduce a non-generic producer or a concrete subclass per type instantiation

Example fix

// before
@ApplicationScoped
class Repo<T> { }
// after
@Dependent
class Repo<T> { }

// before annotating a generic class with a normal scope
if (!clazz.typeParameters().isEmpty()
        && scope != null && !BuiltinScope.DEPENDENT.is(scope)) {
    // fix: make the class @Dependent or remove type params
}

try {
    quarkusBuild.start();
} catch (DefinitionException e) {
    if (e.getMessage().contains("generic, its scope must be @Dependent")) {
        logger.errorf("Make generic bean class @Dependent: %s", e.getMessage());
    }
    throw e;
}

When it happens

Trigger: Beans (public managed-bean creation) computes the bean's scope; scope is non-null and not @Dependent while beanClass.typeParameters() is non-empty.

Common situations: Adding @ApplicationScoped to a generic class like Repository<T>; upgrading Quarkus/ArC where this CDI rule became enforced; copy-pasting scope annotations onto generic base classes.

Related errors

• InterceptionProxy parameter must be a parameterized type: ${
• Producer field type is a parameterized type with a type vari
• @BindingsSource may only define a class type, got ${kind}: $
• A synthetic bean ${bean} was defined with invalid scope anno
• Type of injected Bean<T> does not match the type of the bean

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/56837512e55426ee. Report an issue: GitHub.