apache/dubbo · error · NoSuchMethodException

Method [{}] not found.

Error message

Method [{}] not found.

What it means

Thrown by OBJECT_WRAPPER.invokeMethod when the requested method name is none of getClass, hashCode, toString, or equals. The Object-class wrapper only knows those four methods, so anything else is unknown to it.

Source

Thrown at dubbo-common/src/main/java/org/apache/dubbo/common/bytecode/Wrapper.java:103

        @Override
        public Object invokeMethod(Object instance, String mn, Class<?>[] types, Object[] args)
                throws NoSuchMethodException {
            if ("getClass".equals(mn)) {
                return instance.getClass();
            }
            if ("hashCode".equals(mn)) {
                return instance.hashCode();
            }
            if ("toString".equals(mn)) {
                return instance.toString();
            }
            if ("equals".equals(mn)) {
                if (args.length == 1) {
                    return instance.equals(args[0]);
                }
                throw new IllegalArgumentException("Invoke method [" + mn + "] argument number error.");
            }
            throw new NoSuchMethodException("Method [" + mn + "] not found.");
        }
    };
    private static AtomicLong WRAPPER_CLASS_COUNTER = new AtomicLong(0);

    /**
     * get wrapper.
     *
     * @param c Class instance.
     * @return Wrapper instance(not null).
     */
    public static Wrapper getWrapper(Class<?> c) {
        return ConcurrentHashMapUtils.computeIfAbsent(WRAPPER_MAP, c, (clazz) -> {
            while (ClassGenerator.isDynamicClass(clazz)) // can not wrapper on dynamic class.
            {
                clazz = clazz.getSuperclass();
            }

            if (clazz == Object.class) {

View on GitHub (pinned to 3a3043227f)

Solutions

1. Ensure the class passed to Wrapper.getWrapper is the real service interface/class, not Object.
2. Verify the service interface is on the classpath and loaded by the correct ClassLoader so getWrapper does not fall back to OBJECT_WRAPPER.
3. Check that the method name in the invocation matches an actual method on the target type.

Example fix

// before
Wrapper w = Wrapper.getWrapper(Object.class);
w.invokeMethod(obj, "doWork", types, args);  // throws
// after
Wrapper w = Wrapper.getWrapper(MyServiceImpl.class);
w.invokeMethod(obj, "doWork", types, args);

Wrapper w = Wrapper.getWrapper(targetClass);
if (!Arrays.asList(w.getMethodNames()).contains(methodName)
    && !Arrays.asList(w.getDeclaredMethodNames()).contains(methodName)) {
    // method not present; do not invoke
}

static boolean isKnownMethod(Wrapper w, String mn) {
    return Arrays.asList(w.getMethodNames()).contains(mn);
}

try {
    wrapper.invokeMethod(instance, mn, types, args);
} catch (NoSuchMethodException e) {
    // method unknown to this wrapper; check target type
}

When it happens

Trigger: Calling wrapper.invokeMethod on a Wrapper that resolved to OBJECT_WRAPPER with a method name outside the Object method set (e.g. "foo", "bar"). Occurs when the wrapped class is java.lang.Object or a dynamic class whose non-dynamic superclass is Object.

Common situations: The target interface/class resolved to Object.class after the isDynamicClass loop in getWrapper, so no real method table was generated. Common when a service reference points to a raw Object or an interface that could not be loaded, falling back to Object.

Related errors

• Invoke method [{}] argument number error.
• Property [{}] not found.
• Can not create wrapper for primitive type: {}
• Unknown primitive type: {}
• Can not merge result: {e.getMessage()}

AI-assisted analysis of apache/dubbo@3a3043227f (2026-08-14). Data as JSON: /api/errors/57fa29ddb64dc4c5. Report an issue: GitHub.