JDK 9 RFR of JDK-5040830: (ann) please improve toString() for annotations containing exception proxies

[joe darcy]

Hello,

Some background, when everything is going well, the toString form of an 
annotation looks something like

// Old non-erroneous annotation

@DangerousAnnotation(utopia=BRIGADOON,
thirtyTwoBitsAreNotEnough=42,
classy=interface Fleeting,
classies=[class java.lang.Object, int],
moreClassies=[])

with newlines added for clarity. However, there are various kinds of 
problems that can occur with the data in an annotation and in those 
cases an exception proxy is created so that if the corresponding method 
is called an exception is thrown rather than the data being returned. In 
these cases the string form of an annotation with 
exceptions-that-would-be-thrown-if-methods-are-called looks like:

// Current erroneous annotation

@DangerousAnnotation(utopia=sun.reflect.annotation.EnumConstantNotPresentExceptionProxy at 766a8c91,
thirtyTwoBitsAreNotEnough=sun.reflect.annotation.AnnotationTypeMismatchExceptionProxy at 1f40866a,
classy=sun.reflect.annotation.TypeNotPresentExceptionProxy at 3de4f72b,
classies=[class java.lang.Object, int],
moreClassies=[])

Having the proxy implementation leak through to the string 
representation in this case is not helpful and the string can be made 
more informative. In addition, for Class-related values, the current 
form doesn't use the syntax which is legal in source code for 
annotations. Class-valued annotations are set using Class literal 
syntax, "Foo.class" rather than "class Foo", and arrays of Class-valued 
item should use braces ("{}") rather than brackets, ("[]").

For example, it would be better to have annotation string 
representations which looked like:

// New non-erroneous annotation

@DangerousAnnotation(utopia=BRIGADOON,
thirtyTwoBitsAreNotEnough=42,
classy=Fleeting.class,
classies={java.lang.Object.class, int.class},
moreClassies={})

// New erroneous annotation

@DangerousAnnotation(utopia=BRIGADOON /* Warning: constant not present! */,
thirtyTwoBitsAreNotEnough=/* Warning type mismatch! "class 
java.lang.Integer[42]" */,
classy=Fleeting.class /* Warning: type not present! */,
classies={java.lang.Object.class, int.class},
moreClassies={})

Please review the code to implement these behavioral changes:

     5040830: (ann) please improve toString() for annotations containing 
exception proxies
     http://cr.openjdk.java.net/~darcy/5040830.2

(If you have erroneous Class-value items in an array of Class values, 
then this throws an exception since the exception proxy cannot be stored 
into the Class[].)

Thanks,

-Joe