RFR[9]: 8147585: Annotations with lambda expressions has parameters result in wrong behavior.

[shilpi.rastogi at oracle.com]

Thanks Paul for comments.

Please see http://cr.openjdk.java.net/~srastogi/8147585/webrev.01/

Now processing only public abstract methods of interface.

Thanks,
Shilpi

On 5/30/2016 6:35 PM, Paul Sandoz wrote:
> Hi Shilpi,
>
> You have found the right place but i am not sure your fix is entirely correct.
>
> (Tip: if you use  -Xlog:exceptions=info you can observe the IAE exception when the annotation is processed)
>
> In your test you have:
>
> @Target(value = ElementType.METHOD)
> @Retention(RetentionPolicy.RUNTIME)
> @ interface LambdaWithParameter {
>      Consumer<Integer> f1 = a -> {
>          System.out.println("lambda has parameter");
>      };
> }
>
> @Target(value = ElementType.METHOD)
> @Retention(RetentionPolicy.RUNTIME)
> @ interface LambdaWithoutParameter {
>      Runnable r = () -> System.out.println("lambda without parameter");
> }
>
>
> Both of those annotations will have static synthetic methods generated by the compiler that the indy resolves and links to (look at the javap output). The former will have a method with one parameter.
>
>
> The code in sun/reflect/annotation/AnnotationType.java:
>
> for (Method method : methods) {
>      if (method.getParameterTypes().length != 0)
>          throw new IllegalArgumentException(method + " has params");
>
> has thrown the IAE since 2004, but it’s not clear why it was added as opposed to something more general (see below).
>
>
> The correct fix appears to be to skip over any non-abstract/non-public methods. Thus only public abstract methods get processed.
>
> Your current fix now processes synthetic methods with parameters, in addition to those which were already processed such as synthetic methods without parameters, or even private methods that could have been generated by some tool. I dunno how much say the verifier has in all this, perhaps little or no say.
>
> Thus non-public/non-abstract methods could add inconsistent information to the data structures of AnnotationType. Perhaps this is mostly harmless?
>
> Perhaps Joel (CC’ed) can she some more light on this?
>
> Paul.
>
>
>> On 30 May 2016, at 08:00, shilpi.rastogi at oracle.com wrote:
>>
>> Hi All,
>>
>> Please review fix for https://bugs.openjdk.java.net/browse/JDK-8147585
>> http://cr.openjdk.java.net/~srastogi/8147585/webrev.00/
>>
>> Problem: Annotation with Lamda has parameters results into wrong behavior ( not considered as valid annotation) because
>> According to JLS "By virtue of the AnnotationTypeElementDeclaration production, a method declaration in an annotation type declaration cannot have formal parameters, type parameters, or a throws clause. The following production from §4.3 is shown here for convenience:"
>> (Ref: https://docs.oracle.com/javase/specs/jls/se8/html/jls-9.html#jls-9.6.1)
>>
>>
>> Solution: We should skip synthetic methods during Annotation parsing. According to JLS "An annotation type has no elements other than those defined by the methods it explicitly declares."
>> (Ref https://docs.oracle.com/javase/specs/jls/se8/html/.html#jls-9jls-9.6.1)
>>
>>
>> Thanks,
>> Shilpi