Bug 427380

Description Markus Keller 2014-02-04 10:50:30 EST

The example below deviously puts the type annotation "@A" on foo()'s return type in two possible positions:

1. in the method declaration's modifiers list
2. directly on the return type

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package jsr308.bug.generic;

import java.lang.annotation.*;

@Target({ElementType.TYPE_USE/*, ElementType.METHOD*/})
@Retention(RetentionPolicy.RUNTIME)
@interface A { }

public class Test {
    public @A <T> @A int foo() {
        return 0;
    }
    
    public static void main(String[] args) throws Exception {
        Annotation[] annos = Test.class.getMethod("foo").getAnnotations();
        System.out.println(java.util.Arrays.asList(annos));
        Annotation[] rannos = Test.class.getMethod("foo").getAnnotatedReturnType().getAnnotations();
        System.out.println(java.util.Arrays.asList(rannos));
    }
}

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Both positions are actually legal. But the problem is that @A is not a repeatable annotation. And even when I mark it as @Repeatable(AContainer.class) with 

@Target({ElementType.TYPE_USE})
@Retention(RetentionPolicy.RUNTIME)
@interface AContainer {
    A[] value();
}

, then the "@A <T> @A" on both sides of the type parameter <T> are not properly combined into an AContainer annotation:

Exception in thread "main" java.lang.annotation.AnnotationFormatError: Duplicate annotation for class: interface jsr308.bug.generic.A: @jsr308.bug.generic.A()
	at sun.reflect.annotation.TypeAnnotationParser.mapTypeAnnotations(TypeAnnotationParser.java:361)
	at sun.reflect.annotation.AnnotatedTypeFactory$AnnotatedTypeBaseImpl.<init>(AnnotatedTypeFactory.java:139)
	at sun.reflect.annotation.AnnotatedTypeFactory.buildAnnotatedType(AnnotatedTypeFactory.java:65)
	at sun.reflect.annotation.TypeAnnotationParser.buildAnnotatedType(TypeAnnotationParser.java:79)
	at java.lang.reflect.Executable.getAnnotatedReturnType0(Executable.java:583)
	at java.lang.reflect.Method.getAnnotatedReturnType(Method.java:633)
	at jsr308.bug.generic.Test.main(Test.java:24)