quarkusio/quarkus · error · RuntimeException

${classInfo.name()} should not be extended or implemented

Error message

${classInfo.name()} should not be extended or implemented

What it means

validateResource rejects resource interfaces that are extended or implemented by other types (Jandex finds direct implementors). The resource interface must be a leaf: the extension generates the implementation itself, so user-side subtyping is unsupported and fails the build.

Source

Thrown at extensions/panache/hibernate-orm-rest-data-panache/deployment/src/main/java/io/quarkus/hibernate/orm/rest/data/panache/deployment/HibernateOrmPanacheRestProcessor.java:157

                    new UnremovableBeanBuildItem.BeanClassNameExclusion(repositoryClassName)));

            restDataResourceProducer.produce(new RestDataResourceBuildItem(
                    new ResourceMetadata(resourceClass, resourceInterface, entityType, idType,
                            getEntityFields(index.getIndex(), entityType))));
        }
    }

    private void validateResource(IndexView index, ClassInfo classInfo) {
        if (!Modifier.isInterface(classInfo.flags())) {
            throw new RuntimeException(classInfo.name() + " has to be an interface");
        }

        if (classInfo.interfaceNames().size() > 1) {
            throw new RuntimeException(classInfo.name() + " should only extend REST Data Panache interface");
        }

        if (!index.getKnownDirectImplementors(classInfo.name()).isEmpty()) {
            throw new RuntimeException(classInfo.name() + " should not be extended or implemented");
        }
    }

    private List<Type> getGenericTypes(ClassInfo classInfo) {
        return classInfo.interfaceTypes()
                .stream()
                .findFirst()
                .orElseThrow(() -> new RuntimeException(classInfo.toString() + " does not have generic types"))
                .asParameterizedType()
                .arguments();
    }
}

View on GitHub (pinned to e1c734241f)

Solutions

1. Delete any class implementing the resource interface (the extension generates it)
2. Remove any interface extending the resource interface
3. Customize behavior using entity/repository methods instead of resource subtyping

Example fix

// before
public class PersonResourceImpl implements PersonResource {} // delete this
// after
// no implementing class; customize via the repository bean instead

for (Class<?> impl : knownImplementors(resourceClass))
    throw new IllegalStateException("Resource interface " + resourceClass + " must not be extended or implemented: " + impl);

When it happens

Trigger: Creating 'interface SpecialPersonResource extends PersonResource' or 'class PersonResourceImpl implements PersonResource' where PersonResource is the REST Data Panache resource.

Common situations: Hand-writing an implementation class for a resource interface; trying to inherit/override resource behavior via subinterfaces; accidental implementation in the same codebase.

Related errors

• ${classInfo.name()} has to be an interface
• ${classInfo.name()} should only extend REST Data Panache int
• Couldn't find id field of ${classInfo}
• has to be an interface
• should only extend REST Data Panache interface

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/89ea3207dc25d7bc. Report an issue: GitHub.