Java 17: Cannot read value from annotation

[timonzi]

We currently switch to Java 17 and have the problem with the following constellation:

An object Obj is annotated with Annotation @ObjectAnnotation. This is processed by our annotation processor. A property within the object is annotated with @AnnotationA. AnnotationA contains a property b with type AnnotationB and default value @AnnotationB. AnnotationB contains a property c with type AnnotationC and default value @AnnotationC.

When not trying to access the property b, I get an exception:

java.lang.annotation.AnnotationTypeMismatchException: Incorrectly typed data found for annotation element public abstract org.example2.AnnotationB org.example2.AnnotationA.b() (Found data of type org.example2.AnnotationB)
    at jdk.compiler/com.sun.tools.javac.model.AnnotationProxyMaker$ValueVisitor$1AnnotationTypeMismatchExceptionProxy.generateException(AnnotationProxyMaker.java:271)
    at java.base/sun.reflect.annotation.AnnotationInvocationHandler.invoke(AnnotationInvocationHandler.java:89)
    at jdk.proxy5/jdk.proxy5.$Proxy28.b(Unknown Source)
    at org.example.processor.ObjectProcessor.parseBo(ObjectProcessor.java:62)
    at org.example.processor.ObjectProcessor.process(ObjectProcessor.java:45)
    at jdk.compiler/com.sun.tools.javac.processing.JavacProcessingEnvironment.callProcessor(JavacProcessingEnvironment.java:1023)
    at jdk.compiler/com.sun.tools.javac.processing.JavacProcessingEnvironment.discoverAndRunProcs(JavacProcessingEnvironment.java:939)
    at jdk.compiler/com.sun.tools.javac.processing.JavacProcessingEnvironment$Round.run(JavacProcessingEnvironment.java:1267)
    at jdk.compiler/com.sun.tools.javac.processing.JavacProcessingEnvironment.doProcessing(JavacProcessingEnvironment.java:1382)

This does not happen when:

• We use OpenJDK 11
• Add an (unused) import of AnnotationB in the class (Obj)
• Remove c from AnnotationB

When I use the "normal" reflection mechanism I don't have any problem to resolve the values. But this is not possible in the annotation processor.

The strange thing is also: When I would add another object which looks like the same like Obj and I would catch the exception for the first processed object, it works like expected for the second one. Here I don't get an exception.

Is there any advice how to handle the exception? Is there a compatibility issue with Java 17?

I created reproducer projects for this: https://github.com/timonzi/annotation-processor-jdk17 Reproduction steps: Execute a (clean) install on...

• annotation-holder
• annotation-processor
• java (here the exceptions occurs)

[timonzi]

If anyone has the same problem: It can be solved, when the a value of the default value annotation is overridden.

Example:

AnnotationB b() default @AnnotationB(dummyValue = "someValue");

It does not work with

AnnotationB b() default @AnnotationB;

[JakeWharton]

I'm not clear what JavaPoet has to do with all of this.

[timonzi]

Yeah, me neither in the meantime. I thought JavaPoet would do more here, but after looking at the code more closely I don't think JavaPoet has anything to do with it either.

That's why I'm closing the issue again.