quarkusio/quarkus · error · IllegalArgumentException

Parameter type <type> is not supported for method<method> of

Error message

Parameter type <type> is not supported for method<method> of class<class>

What it means

After iterating the parameters of a @ControllerAdvice exception-handler method, preGenerateMethodBody throws IllegalArgumentException if any parameter was neither an Exception subtype, HttpServletRequest, nor HttpServletResponse — those are the only parameter types the generated exception mapper can supply. The deployment fails and names the unsupported type, method, and class.

Source

Thrown at extensions/spring-web/core/deployment/src/main/java/io/quarkus/spring/web/deployment/ControllerAdviceExceptionMapperGenerator.java:135

                            + " is being used multiple times in method" + controllerAdviceMethod.name() + " of class"
                            + controllerAdviceMethod.declaringClass().name());
                }

                // we need to generate a field that injects the HttpServletResponse into the class
                FieldDesc httpResponseField = cc.field("httpServletResponse", fc -> {
                    fc.setType(HttpServletResponse.class);
                    fc.private_();
                    fc.addAnnotation(Context.class);
                });

                // stash the fieldCreator in a map indexed by the parameter type so we can retrieve it later
                parameterTypeToField.put(parameterType, httpResponseField);
            } else {
                notAllowedParameterIndex = i;
            }
        }
        if (notAllowedParameterIndex >= 0) {
            throw new IllegalArgumentException(
                    "Parameter type " + parameterTypes.get(notAllowedParameterIndex).name() + " is not supported for method"
                            + controllerAdviceMethod.name() + " of class" + controllerAdviceMethod.declaringClass().name());
        }

        createHttpHeadersField(cc);
    }

    private void createHttpHeadersField(ClassCreator classCreator) {
        httpHeadersField = classCreator.field("httpHeaders", fc -> {
            fc.setType(HttpHeaders.class);
            fc.private_();
            fc.addAnnotation(Context.class);
        });
    }

    @Override
    void generateMethodBody(BlockCreator bc, Expr thisRef, Expr exceptionParam) {
        if (isVoidType(returnType)) {

View on GitHub (pinned to e1c734241f)

Solutions

1. Remove unsupported parameters, keeping only Exception subtypes, HttpServletRequest, and HttpServletResponse
2. Replace Spring-specific types like WebRequest/HandlerMethod with HttpServletRequest equivalents
3. Obtain extra data (e.g. session attributes) inside the method body from the injected request instead of via parameters

Example fix

// before
@ExceptionHandler(Exception.class)
void handle(Exception e, WebRequest request) {...}
// after
@ExceptionHandler(Exception.class)
void handle(Exception e, HttpServletRequest req) {...}

for (Class<?> p : handlerParams) {
  boolean ok = Exception.class.isAssignableFrom(p) || HttpServletRequest.class.isAssignableFrom(p)
            || HttpServletResponse.class.isAssignableFrom(p);
  if (!ok) throw new IllegalStateException("Unsupported @ControllerAdvice param: " + p);
}

boolean isSupportedParam(Class<?> t) {
  return Exception.class.isAssignableFrom(t)
      || HttpServletRequest.class.isAssignableFrom(t)
      || HttpServletResponse.class.isAssignableFrom(t);
}

When it happens

Trigger: Declaring an @ExceptionHandler method with a parameter of an unsupported type, e.g. @ExceptionHandler(MyException.class) void handle(MyException e, Model model) or HttpSession, Principal, Locale, etc.

Common situations: Migrating Spring @ControllerAdvice handlers verbatim; Spring-specific parameter types (WebRequest, HandlerMethod, Model) that Quarkus' generator does not support; leftover unused parameters from refactoring.

Related errors

• Parameter type '<type>' is not supported for method '<method
• Parameter type <type> is being used multiple times in method
• @ExceptionHandler methods in @ControllerAdvice must be publi
• You can only have a single class annotated with @ControllerA
• Spring Web can only work if 'quarkus-resteasy-jackson' or 'q

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/e1edd27f2464cc71. Report an issue: GitHub.