quarkusio/quarkus · error · java.lang.IllegalStateException

No parameter injector found for parameter %s of route method

Error message

No parameter injector found for parameter %s of route method %s declared on %s

What it means

Raised by ReactiveRoutesProcessor.validateRouteMethod when, while iterating the route method's parameters, no registered ParameterInjector matches a parameter's type and annotations. Reactive Routes only injects parameters it recognizes (RoutingContext, @Param, @Header, body types, etc.); an unmatched parameter would arrive as null at runtime, so the build-time validation fails fast, naming the parameter index, method and declaring bean.

Source

Thrown at extensions/reactive-routes/deployment/src/main/java/io/quarkus/vertx/web/deployment/ReactiveRoutesProcessor.java:563

            DotName returnTypeName = method.returnType().name();

            if ((returnTypeName.equals(DotNames.UNI)
                    || returnTypeName.equals(DotNames.MULTI)
                    || returnTypeName.equals(DotNames.COMPLETION_STAGE))
                    && method.returnType().kind() == Kind.CLASS) {
                throw new IllegalStateException(String.format(
                        "Route business method returning a Uni/Multi/CompletionStage must declare a type argument on the return type [method: %s, bean: %s]",
                        method, bean));
            }
            boolean canEndResponse = false;
            int idx = 0;
            int failureParams = 0;
            for (Type paramType : params) {
                Set<AnnotationInstance> paramAnnotations = Annotations.getParameterAnnotations(transformedAnnotations,
                        method, idx);
                List<ParameterInjector> injectors = getMatchingInjectors(paramType, paramAnnotations, index);
                if (injectors.isEmpty()) {
                    throw new IllegalStateException(String.format(
                            "No parameter injector found for parameter %s of route method %s declared on %s", idx,
                            method, bean));
                }
                if (injectors.size() > 1) {
                    throw new IllegalStateException(String.format(
                            "Multiple parameter injectors found for parameter %s of route method %s declared on %s",
                            idx, method, bean));
                }
                ParameterInjector injector = injectors.get(0);
                if (injector.getTargetHandlerType() != null && !injector.getTargetHandlerType().equals(handlerType)) {
                    throw new IllegalStateException(String.format(
                            "HandlerType.%s is not legal for parameter %s of route method %s declared on %s",
                            injector.getTargetHandlerType(), idx, method, bean));
                }

                // A param injector may validate the parameter annotations
                injector.validate(bean, method, routeAnnotation, paramType, paramAnnotations);

View on GitHub (pinned to e1c734241f)

Solutions

1. Annotate the parameter with a supported annotation such as @Param or @Header
2. Change the parameter type to a supported injectable type like RoutingContext
3. Register a custom ParameterInjector extension if a custom parameter type must be supported

When it happens

Trigger: Thrown at extensions/reactive-routes/deployment/src/main/java/io/quarkus/vertx/web/deployment/ReactiveRoutesProcessor.java:563 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/81c4735f34e7bb1b. Report an issue: GitHub.