Hi Eric,
I can reproduce the bug,
as you said, in ProxyGenerator.generateClassFile() only the instance methods
should be collected.
cheers,
Rémi
----- Mail original -----
> De: "Eric McCorkle" <e...@metricspace.net>
> À: "core-libs-dev" <core-libs-dev@openjdk.java.net>
> Envoyé: Lundi 2 Octobre 2017 20:44:26
> Objet: Confirm bug in java.lang.reflect.Proxy wrt static methods in interfaces
> Hello everyone,
>
> A colleague of mine discovered what seems to be a bug in
> java.lang.reflect.Proxy#newProxyInstance. I'd like to confirm that this
> is indeed incorrect behavior before I go and fix it.
>
> Consider the following two interfaces:
>
> interface I1 {
> static I1 foo() {
> return null;
> }
> }
>
> interface I2 {
> static I2 foo() {
> return null;
> }
> }
>
> JLS 9.4.1 states that static methods are not inherited in interfaces,
> thus it should be perfectly legal to define some class which inherits I1
> and I2.
>
> The following proxy creation fails:
>
> public class ProxyBug {
> public static void main(String... args) {
> I2 i2 =(I2)Proxy.newProxyInstance(
> ClassLoader.getSystemClassLoader(),
> new Class[] {I1.class, I2.class},
> new InvocationHandler() {
> @Override
> public Object invoke(Object proxy,
> Method method,
> Object[] args)
> throws Throwable {
> return null;
> }
> });
> }
> }
>
> The exception generated is as follows:
>
> Exception in thread "main" java.lang.IllegalArgumentException: methods
> with same signature foo() but incompatible return types: [interface I1,
> interface I2]
> at sun.misc.ProxyGenerator.checkReturnTypes(ProxyGenerator.java:712)
> at sun.misc.ProxyGenerator.generateClassFile(ProxyGenerator.java:461)
> at sun.misc.ProxyGenerator.generateProxyClass(ProxyGenerator.java:339)
> at java.lang.reflect.Proxy$ProxyClassFactory.apply(Proxy.java:639)
> at java.lang.reflect.Proxy$ProxyClassFactory.apply(Proxy.java:557)
> at java.lang.reflect.WeakCache$Factory.get(WeakCache.java:230)
> at java.lang.reflect.WeakCache.get(WeakCache.java:127)
> at java.lang.reflect.Proxy.getProxyClass0(Proxy.java:419)
> at java.lang.reflect.Proxy.newProxyInstance(Proxy.java:719)
> at ProxyBug.main(ProxyBug.java:19)
>
> So it would seem that newProxyInstance is incorrectly including static
> methods in its check for incompatible return types.
>
> Can I get someone from core-libs to confirm that this is not intended
> before I file a bug and start on the fix?
