Discussion:
Issue with ObjectReferenceImpl.invokeMethod in jdk8
Mike Yawn
2015-01-23 12:00:35 UTC
Permalink
(cross posting from serviceability-dev list; I was told I might have
better luck here so apologies to anyone getting duplicates)

I'm seeing a regression moving from JDK7 to JDK8u40 with the invocation
of a method in an annotation from a debugger.

I have a simple annotation class with two methods. There is a unit
test that retrieves the annotations (getDeclaredAnnotations()).
After retrieving the annotations, I try to call
ObjectReference.invokeMethod() to invoke each of the annotation's
methods. In JDK7 this worked; in JDK8 it fails with an
IllegalAccessException: "Not a default method".

I've looked at the source for com.sun.tools.jdi.ObjectReferenceImpl and
see significant changes between JDK7 and JDK8 due to the introduction of
interface methods in JDK8.

In JDK7, all methods were class (as opposed to interface) methods and
the validation of the annotation methods was successful.

In JDK8, validateMethodInvocation has been rewritten to be a small
method that forwards the validation to one of two new methods,
validateClassMethodInvocation or validateIFaceMethodInvocation. The
implementation of validateClassMethodInvocation appears to be the same
as the pre-JDK8 validateMethodInvocation -- validation that the
annotation method would pass. However, the annotation method is being
treated as an interface method (because method.declaringType()
instanceof InterfaceTypeImpl is true) and going through
validateIFaceMethodInvocation. The test there is that
method.isDefault() -- and the annotation method returns false, thus the
exception is thrown.

I'm not sure what the correct behavior is here, but there are a couple
of possibilities:
- If annotation classes were treated as classes, rather than interfaces,
then we'd go through the same validation as before and this would work.
- Alternately. if methods on annotations were considered default
methods, then we'd pass the new validation. (The annotations do have a
"default" value specified, but not all annotation methods will, so this
seems a less satisfactory solution)
- Or, the validateIFaceMethodInvocation may need a special test for
annotation methods and validate them differently than interface methods.


Do I need to file a bug for this, or is this mailing list a better place
to report/discuss the issue, or am I doing something wrong that I just
got away with in JDK7 but JDK8 is closing a loophole, so to speak?

Thanks,
Mike Yawn

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