{"record":{"id":"2ca8d8bf6fef18b6","repo":"quarkusio/quarkus","slug":"mixing-quarkus-rest-and-resteasy-classic-server-pa","errorCode":null,"errorMessage":"Mixing Quarkus REST and RESTEasy Classic server parts is not supported","messagePattern":"Mixing Quarkus REST and RESTEasy Classic server parts is not supported","errorType":"exception","errorClass":"DeploymentException","httpStatus":null,"severity":"error","filePath":"extensions/resteasy-reactive/rest-common/deployment/src/main/java/io/quarkus/resteasy/reactive/common/deployment/ResteasyReactiveCommonProcessor.java","lineNumber":110,"sourceCode":"\n    @Produce(ServiceStartBuildItem.class)\n    @BuildStep\n    void checkMixingStacks(Capabilities capabilities, CurateOutcomeBuildItem curateOutcomeBuildItem,\n            List<IgnoreStackMixingBuildItem> ignoreStackMixingItems) {\n        if (!ignoreStackMixingItems.isEmpty()) {\n            return;\n        }\n        List<ResolvedDependency> resteasyClassicDeps = curateOutcomeBuildItem.getApplicationModel().getDependencies().stream()\n                .filter(d -> d.getGroupId().equals(\"org.jboss.resteasy\")).toList();\n        boolean hasResteasyCoreDep = resteasyClassicDeps.stream()\n                .anyMatch(IS_NOT_TEST_SCOPED.and(IS_RESTEASY_CLASSIC_CORE_DEP));\n        if (!hasResteasyCoreDep) {\n            return;\n        }\n        boolean hasResteasyClassicClient = resteasyClassicDeps.stream()\n                .anyMatch(IS_NOT_TEST_SCOPED.and(IS_RESTEASY_CLASSIC_CLIENT_DEP));\n        if (!hasResteasyClassicClient) { // there is no bulletproof way of knowing whether a server specific dependency has been included, so we deduce it by the absence of client dependency\n            throw new DeploymentException(\"Mixing Quarkus REST and RESTEasy Classic server parts is not supported\");\n        }\n        if (capabilities.isPresent(Capability.REST_CLIENT_REACTIVE)) {\n            throw new DeploymentException(\n                    \"Mixing Quarkus REST and RESTEasy Classic client parts is not supported\");\n        } else {\n            LOG.warn(\n                    \"Mixing Quarkus REST server and RESTEasy Classic client parts might lead to unexpected results. Consider using 'quarkus-rest-client' instead of 'quarkus-resteasy-client'.\");\n        }\n    }\n\n    @BuildStep\n    void searchForProviders(Capabilities capabilities,\n            BuildProducer<AdditionalApplicationArchiveMarkerBuildItem> producer) {\n        if (capabilities.isPresent(Capability.RESTEASY) || capabilities.isPresent(Capability.RESTEASY_CLIENT)\n                || QuarkusClassLoader.isClassPresentAtRuntime(\n                        \"org.jboss.resteasy.plugins.providers.JaxrsServerFormUrlEncodedProvider\")) { // RESTEasy Classic could be imported via non-Quarkus dependencies\n            // in this weird case we don't want the providers to be registered automatically as this would lead to multiple bean definitions\n            return;","sourceCodeStart":92,"sourceCodeEnd":128,"githubUrl":"https://github.com/quarkusio/quarkus/blob/e1c734241f34c7919086ceb4c9262b4a58f6de44/extensions/resteasy-reactive/rest-common/deployment/src/main/java/io/quarkus/resteasy/reactive/common/deployment/ResteasyReactiveCommonProcessor.java#L92-L128","documentation":"Quarkus detects that a deployment contains both Quarkus REST (RESTEasy Reactive) server dependencies and RESTEasy Classic server dependencies without the Classic client marker, which is an unsupported mixed stack. The classic-client dependency is used as a heuristic: its absence implies a classic server part was pulled in. Deployment aborts with a DeploymentException.","triggerScenarios":"Adding `quarkus-resteasy` (classic) alongside `quarkus-rest`/`quarkus-resteasy-reactive` to the same application, e.g. accidentally via a transitive dependency or starter, with no `quarkus-resteasy-client` dependency.","commonSituations":"Adding an older library/quickstart module that still uses RESTEasy Classic; migration halfway between stacks; an extension transitively bringing in classic server deps.","solutions":["Remove the RESTEasy Classic server dependency (`quarkus-resteasy`) and migrate endpoints to Quarkus REST (`quarkus-rest`)","If Classic is intentional, it must be the whole stack — remove the reactive server extensions","Check `mvn dependency:tree` for who pulls in `quarkus-resteasy` transitively and exclude it"],"exampleFix":"// before (pom.xml)\n<dependency>io.quarkus:quarkus-rest</dependency>\n<dependency>io.quarkus:quarkus-resteasy</dependency>\n// after\n<dependency>io.quarkus:quarkus-rest</dependency>","handlingStrategy":"validation","validationCode":"// run before build:\n// mvn dependency:tree -Dincludes=io.quarkus:quarkus-resteasy\ngrep -q 'quarkus-resteasy<' pom.xml && ! grep -q 'quarkus-rest<' pom.xml || echo 'conflict risk'","typeGuard":null,"tryCatchPattern":null,"preventionTips":["Never mix quarkus-rest and quarkus-resteasy in one app","Run mvn dependency:tree in CI to detect transitive classic deps","Standardize team on Quarkus REST (reactive) stack"],"tags":["dependency-conflict","resteasy-classic","resteasy-reactive","quarkus"],"backgroundTag":"mixed-rest-stack-dependency","analyzedSha":"e1c734241f34c7919086ceb4c9262b4a58f6de44","analyzedAt":"2026-09-05T17:01:29.979Z","contentChangedAt":"2026-09-05T17:01:29.979Z","schemaVersion":2},"datasetVersion":"2026-09-12T22:17:10.623Z"}