quarkusio/quarkus · error · IllegalStateException

Cannot generate HAL endpoints without either 'quarkus-rest-j

Error message

Cannot generate HAL endpoints without either 'quarkus-rest-jackson' or 'quarkus-rest-jsonb'

What it means

LinksProcessor.validateJsonNeededForHal throws this at build time when HAL links are requested (quarkus.rest.links.hal.enabled or a resource method produces HAL media type) but no JSON serializer extension is present. Generating HAL representations requires either quarkus-rest-jackson or quarkus-rest-jsonb to serialize the response.

Source

Thrown at extensions/resteasy-reactive/rest-links/deployment/src/main/java/io/quarkus/resteasy/reactive/links/deployment/LinksProcessor.java:98

        linksProviderRecorder.setLinksContainer(linksContainer);
    }

    @BuildStep
    AdditionalBeanBuildItem registerRestLinksProviderProducer() {
        return AdditionalBeanBuildItem.unremovableOf(RestLinksProviderProducer.class);
    }

    @BuildStep
    @Produce(ArtifactResultBuildItem.class)
    void validateJsonNeededForHal(Capabilities capabilities,
            ResteasyReactiveResourceMethodEntriesBuildItem resourceMethodEntriesBuildItem) {
        boolean isHalSupported = capabilities.isPresent(Capability.HAL);
        if (isHalSupported && isHalMediaTypeUsedInAnyResource(resourceMethodEntriesBuildItem.getEntries())) {

            if (!capabilities.isPresent(Capability.RESTEASY_REACTIVE_JSON_JSONB) && !capabilities.isPresent(
                    Capability.RESTEASY_REACTIVE_JSON_JACKSON)) {

                throw new IllegalStateException("Cannot generate HAL endpoints without "
                        + "either 'quarkus-rest-jackson' or 'quarkus-rest-jsonb'");
            }
        }
    }

    @BuildStep
    void addHalSupport(Capabilities capabilities,
            BuildProducer<CustomContainerResponseFilterBuildItem> customResponseFilters,
            BuildProducer<AdditionalBeanBuildItem> additionalBeans) {
        boolean isHalSupported = capabilities.isPresent(Capability.HAL);
        if (isHalSupported) {
            customResponseFilters.produce(
                    new CustomContainerResponseFilterBuildItem(HalServerResponseFilter.class.getName()));

            additionalBeans.produce(AdditionalBeanBuildItem.unremovableOf(ResteasyReactiveHalService.class));
        }
    }

View on GitHub (pinned to e1c734241f)

Solutions

1. Add io.quarkus:quarkus-rest-jackson (or quarkus-rest-jsonb) as a dependency.
2. If HAL is unintended, disable it via quarkus.rest.links.hal.enabled=false or remove the HAL media type from resource methods.
3. Ensure the correct reactive-stack extension family matches your REST setup.

Example fix

// before (pom.xml): only quarkus-rest present
// after
<dependency>
  <groupId>io.quarkus</groupId>
  <artifactId>quarkus-rest-jackson</artifactId>
</dependency>

// pom.xml sanity check before using HAL
// require quarkus-rest-jackson or quarkus-rest-jsonb dependency present

When it happens

Trigger: Using quarkus-rest with quarkus-rest-links and producing HAL media type, while having no Jackson or JSON-B REST extension dependency; e.g. switching from quarkus-resteasy-jackson to quarkus-rest and forgetting to add quarkus-rest-jackson.

Common situations: Migrating to RESTEasy Reactive/quarkus-rest and losing the JSON module; an app producing only custom/media writers but also declaring HAL links.

Understand the failure class

Background: "not installed", "pip install", "required for": how missing-dependency errors surface across open-source libraries — this error's family across 34 libraries.

Related errors

• Cannot generate HAL endpoints without either 'quarkus-restea
• Cannot generate HAL endpoints without either 'quarkus-rest-j
• Providing multiple BuiltInReaderOverrideBuildItem for the sa
• @Compressed and @Uncompressed cannot be both declared on res
• The combination of '@${annotationName}' and '@ServerRequestF

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/ac4d851142ab73a2. Report an issue: GitHub.