jdkProxyObj.getClass().getMethod("xxx") will throw java.lang.NoSuchMethodException: jdk.proxy4.$Proxy61.xxx() in the native-image.

[wangliang181230]

Jdk proxy object can't get method by the Method Class.getMethod(methodName) in the native-image.

jdkProxyObj.getClass().getMethod("xxx") will throw java.lang.NoSuchMethodException: jdk.proxy4.$Proxy61.xxx() in the native-image.

Example project

https://github.com/wangliang181230/example__oracle_graal_issue-6079

Some code

TestInterface.java

public interface TestInterface {

    void foo();

    void bar();

}

ProxyReflectionExample.java

import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

public class ProxyReflectionExample {

    public static void main(String[] args) throws Exception {
        TestInterface proxyObj = (TestInterface)Proxy.newProxyInstance(
            ProxyReflectionExample.class.getClassLoader(),
            new Class[] { TestInterface.class },
            (proxy, method, args1) -> {
                System.out.println("Method: " + method.getName() + ",     Declaring Class: " + method.getDeclaringClass().getName());
                return null;
            });

        try {
            // It will throw `NoSuchMethodException` in `native-image`.
            Method method = proxyObj.getClass().getMethod("foo");
            System.out.println("Method: " + method.getName() + ",     Declaring Class: " + method.getDeclaringClass().getName());
            method.invoke(proxyObj);

            method = proxyObj.getClass().getMethod("bar");
            System.out.println("Method: " + method.getName() + ",     Declaring Class: " + method.getDeclaringClass().getName());
            method.invoke(proxyObj);
        } catch (Throwable t) {
            t.printStackTrace();
        }

        Thread.sleep(10000);
    }
}

reflect-config.json

[
    {
        "name": "TestInterface",
        "methods": [
            { "name": "foo", "parameterTypes": [] },
            { "name": "bar", "parameterTypes": [] }
        ]
    }
]

Console output in JVM

Method: foo,     Declaring Class: jdk.proxy1.$Proxy0
Method: foo,     Declaring Class: TestInterface
Method: bar,     Declaring Class: jdk.proxy1.$Proxy0
Method: bar,     Declaring Class: TestInterface

Error log in native-image

java.lang.NoSuchMethodException: jdk.proxy4.$Proxy60.foo()
        at java.base@17.0.6/java.lang.Class.getMethod(DynamicHub.java:2227)
        at ProxyReflectionExample.main(ProxyReflectionExample.java:17)

Environment and versions:

1. OS: Windows 10
2. GraalVM: graalvm-ce-java17-22.3.1 Windows (amd64)

How can I solve this problem?

[SergejIsbrecht]

Do you expect the Proxy to be registered automatically? If not, you would need to register it manually. Please see https://www.graalvm.org/22.0/reference-manual/native-image/DynamicProxy/ -

Also, please add the GraalVM version, which you used.

[wangliang181230]

Do you expect the Proxy to be registered automatically? If not, you would need to register it manually. Please see https://www.graalvm.org/22.0/reference-manual/native-image/DynamicProxy/ -

My question is not about dynamic proxy, but about the acquisition of dynamic proxy methods.
For example proxyObj.getClass().getMethod(methodName) will throw NoSuchMethodException in native-image.
Of course, I have added the metadata of the interfaces to reflect-config.json and proxy-config.json and successfully created the proxy object in native-image, but the class of the proxy object is dynamic and cannot be added the reflect metadata.

Also, please add the GraalVM version, which you used.

graalvm-ce-java17-22.3.1 Windows (amd64)

[wangliang181230]

This will cause the semantic inconsistency of proxyObject.getClass().getMethod(methodName) in JVM and native-image.

[SergejIsbrecht]

Could you maybe add the stacktrace and the config files to this issue?

[wangliang181230]

Could you maybe add the stacktrace and the config files to this issue?

I modified the content of this issue. PTAL

[oubidar-Abderrahim]

Thank you for sharing this, we'll take a look into it shortly

[vjovanov]

This is currently not supported in the metadata. We should allow for proxies to be marked with an interface list:

  {
        "proxy": ["TestInterface"],
        "methods": [
            { "name": "foo", "parameterTypes": [] },
            { "name": "bar", "parameterTypes": [] }
        ]
    }

Until we introduce that feature, a possible workaround is to use initialization at build time. Rewrite the program in the following way:

import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

interface TestInterface {

    void foo();

    void bar();

}

public class ProxyReflectionExample {

    static class ProxyReflectionStatics {
        static final TestInterface proxyObj = (TestInterface) Proxy.newProxyInstance(
                        ProxyReflectionExample.class.getClassLoader(),
                        new Class[]{TestInterface.class},
                        (proxy, method, args1) -> {
                            System.out.println("Method: " + method.getName() + ",     Declaring Class: " + method.getDeclaringClass().getName());
                            return null;
                        });

    }

    public static void main(String[] args) throws Exception {
        try {
            // It will throw `NoSuchMethodException` in `native-image`.
            Method method = ProxyReflectionStatics.proxyObj.getClass().getMethod("foo");
            System.out.println("Method: " + method.getName() + ",     Declaring Class: " + method.getDeclaringClass().getName());
            method.invoke(ProxyReflectionStatics.proxyObj);

            method = ProxyReflectionStatics.proxyObj.getClass().getMethod("bar");
            System.out.println("Method: " + method.getName() + ",     Declaring Class: " + method.getDeclaringClass().getName());
            method.invoke(ProxyReflectionStatics.proxyObj);
        } catch (Throwable t) {
            t.printStackTrace();
        }

        Thread.sleep(10000);
    }
}

and build it with:

native-image ProxyReflectionExample --initialize-at-build-time=ProxyReflectionExample\$ProxyReflectionStatics

[wangliang181230]

@vjovanov
However, in many applications, it is not known which interface to proxy.
The above code is only an example I provided.

[sdeleuze]

Looks like Spring Framework AOP support is impacted by this bug, see this comment for more details. Could this use case be supported out of the box?

[vjovanov]

We definitely need to make this a priority. @sdeleuze I am not sure what out of the box means here?

[sdeleuze]

I mean without additonal hints specified via JSON files if possible.

[vjovanov]

That would mean that we have to register all methods of a proxy for reflection. This would lead to bloating of the image which we try to avoid in all places.

Is there a difference between this JSON entry and other entries? Why would it be hard to specify the entry in JSON?

[sdeleuze]

Indeed, we should be careful about the footprint.

If we specify metadata explicitly, don't we need all the usual variants (invoke versus introspect, declared versus public versus individual methods)?

Should we make introspect the default with the upcoming new reflection mode?

If we need all the variants, should they be in proxy-config.json, or in reflect-config.json with a list of proxy interfaces instead of a classname (which in this case is not something known before native-image invocation?

Will those new entries be backward compatible with GraalVM 22.3.0 and Jube 2023 releases?

[loicottet]

Fixed by #8822