What causes "Cannot invoke method: ${className}#${name} on ${instance}" in quarkusio/quarkus?

Inspect the cause (InvocationTargetException#getTargetException) for the real failure

quarkusio/quarkus · error · java.lang.RuntimeException

Cannot invoke method: ${className}#${name} on ${instance}

Error message

Cannot invoke method: ${className}#${name} on ${instance}

What it means

When Reflections.invokeMethod() calls a method reflectively and the method itself throws a checked exception (wrapped in InvocationTargetException, and not a RuntimeException), ArC rethrows it as this RuntimeException naming the class, method, and target instance. The original failure is attached as the cause.

Source

Thrown at independent-projects/arc/runtime/src/main/java/io/quarkus/arc/impl/Reflections.java:188

            field.set(instance, value);
        } catch (NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException e) {
            throw new RuntimeException("Cannot set field value: " + clazz.getName() + "#" + name, e);
        }
    }

    public static Object invokeMethod(Class<?> clazz, String name, Class<?>[] paramTypes, Object instance, Object[] args) {
        try {
            Method method = clazz.getDeclaredMethod(name, paramTypes);
            if (!method.canAccess(instance)) {
                method.setAccessible(true);
            }
            return method.invoke(instance, args);
        } catch (InvocationTargetException e) {
            Throwable t = e.getTargetException();
            if (t instanceof RuntimeException) {
                throw (RuntimeException) t;
            }
            throw new RuntimeException("Cannot invoke method: " + clazz.getName() + "#" + name + " on " + instance, e);
        } catch (NoSuchMethodException | SecurityException | IllegalArgumentException | IllegalAccessException e) {
            throw new RuntimeException("Cannot invoke method: " + clazz.getName() + "#" + name + " on " + instance, e);
        }
    }

    @SuppressWarnings("unchecked")
    static <T> T cast(Object obj) {
        return (T) obj;
    }

    @SuppressWarnings("unchecked")
    public static <T> Class<T> getRawType(Type type) {
        if (type instanceof Class<?>) {
            return (Class<T>) type;
        }
        if (isParameterizedType(type)) {
            final ParameterizedType parameterizedType = asParameterizedType(type);
            if (parameterizedType.getRawType() instanceof Class<?>) {

View on GitHub (pinned to e1c734241f)

Solutions

Inspect the cause (InvocationTargetException#getTargetException) for the real failure
Fix the underlying checked exception thrown by the target method
Catch and handle the checked exception inside the invoked method, or change it to throw a RuntimeException
Validate inputs/instance state before the reflective call so the method succeeds

Example fix

// before
public void doWork() throws IOException { Files.readAllBytes(path); }
// after
public void doWork() { try { Files.readAllBytes(path); } catch (IOException e) { throw new UncheckedIOException(e); } }

Defensive patterns

Strategy: try-catch

Try / catch

try { return Reflections.invokeMethod(clazz, name, types, instance, args); }
catch (RuntimeException e) {
    Throwable cause = e.getCause();
    if (cause != null) log.error("Target threw " + cause, cause);
    throw e;
}

Prevention

Inspect the cause chain — the real failure is the wrapped target exception
Convert checked exceptions to unchecked inside invoked methods
Validate instance state before reflective invocation

When it happens

Trigger: Invoking a method via Reflections.invokeMethod() whose target throws a checked/non-Runtime Throwable; the InvocationTargetException path re-wraps it since only RuntimeExceptions are unwrapped and rethrown directly.

Common situations: Bean callbacks or interceptor-invoked methods throwing checked exceptions during tests; reflective invocation of a method doing I/O that fails; debugging why a wrapped checked exception surfaced from container code.

Related errors

AI-assisted analysis of quarkusio/quarkus@e1c734241f (2026-09-05). Data as JSON: /api/errors/2b12bbf0d1dfb3ff. Report an issue: GitHub.