Consistent parameter retrieval across InvocableHandlerMethod variants

See gh-22900

spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/reactive/InvocableHandlerMethod.java

@@ -109,12 +109,8 @@ public class InvocableHandlerMethod extends HandlerMethod {
 	}
 
 	/**
-	 * Configure a reactive registry. This is needed for cases where the response
-	 * is fully handled within the controller in combination with an async void
-	 * return value.
-	 * <p>By default this is an instance of {@link ReactiveAdapterRegistry} with
-	 * default settings.
-	 * @param registry the registry to use
+	 * Configure a reactive adapter registry. This is needed for async return values.
+	 * <p>By default this is a {@link ReactiveAdapterRegistry} with default settings.
 	 */
 	public void setReactiveAdapterRegistry(ReactiveAdapterRegistry registry) {
 		this.reactiveAdapterRegistry = registry;
@@ -125,11 +121,10 @@ public class InvocableHandlerMethod extends HandlerMethod {
 	 * Invoke the method for the given exchange.
 	 * @param message the current message
 	 * @param providedArgs optional list of argument values to match by type
-	 * @return a Mono with the result from the invocation.
+	 * @return a Mono with the result from the invocation
 	 */
 	@SuppressWarnings("KotlinInternalInJava")
 	public Mono<Object> invoke(Message<?> message, Object... providedArgs) {
-
 		return getMethodArgumentValues(message, providedArgs).flatMap(args -> {
 			Object value;
 			try {
@@ -157,16 +152,17 @@ public class InvocableHandlerMethod extends HandlerMethod {
 
 			MethodParameter returnType = getReturnType();
 			ReactiveAdapter adapter = this.reactiveAdapterRegistry.getAdapter(returnType.getParameterType());
-			return isAsyncVoidReturnType(returnType, adapter) ?
-					Mono.from(adapter.toPublisher(value)) : Mono.justOrEmpty(value);
+			return (isAsyncVoidReturnType(returnType, adapter) ?
+					Mono.from(adapter.toPublisher(value)) : Mono.justOrEmpty(value));
 		});
 	}
 
 	private Mono<Object[]> getMethodArgumentValues(Message<?> message, Object... providedArgs) {
+		MethodParameter[] parameters = getMethodParameters();
 		if (ObjectUtils.isEmpty(getMethodParameters())) {
 			return EMPTY_ARGS;
 		}
-		MethodParameter[] parameters = getMethodParameters();
+
 		List<Mono<Object>> argMonos = new ArrayList<>(parameters.length);
 		for (MethodParameter parameter : parameters) {
 			parameter.initParameterNameDiscovery(this.parameterNameDiscoverer);
@@ -196,7 +192,7 @@ public class InvocableHandlerMethod extends HandlerMethod {
 	private void logArgumentErrorIfNecessary(MethodParameter parameter, Throwable ex) {
 		// Leave stack trace for later, if error is not handled...
 		String exMsg = ex.getMessage();
-		if (!exMsg.contains(parameter.getExecutable().toGenericString())) {
+		if (exMsg != null && !exMsg.contains(parameter.getExecutable().toGenericString())) {
 			if (logger.isDebugEnabled()) {
 				logger.debug(formatArgumentError(parameter, exMsg));
 			}