Thanks for clearing this up Aleksey, I should have posted an example right away so here is some code that reproduces the NullPointerException where I would either expect: (a) an IncompleteAnnotationException or (b) a return value of false. I guess returning false makes more sense as one expects to being able to call the equals (and hashCode / toString) methods even for incomplete annotations:
https://gist.github.com/raphw/baeb31d81322d3dba482 By the javadoc documentation of the memberValueEquals method in the AnnotationInvocationHandler class, I would argue that at least the resulting NullPointerException is not desired. Thanks for the clarification, Rafael 2014-11-17 10:52 GMT+01:00 Aleksey Shipilev <aleksey.shipi...@oracle.com>: > Hi Joe, > > I am missing something. Of course, JLS requires the reference types > members of annotations to be non-null. But IncompleteAnnotationEx is > here to cover the case when the annotation is mis-constructed. > > Therefore, I think the original Rafael's question is still unanswered. I > can see how the NPE can be produced while calling equals on > mis-constructed annotation backed by AnnotationInvocationHandler: > > private Boolean equalsImpl(Object o) { > ... > for (Method memberMethod : getMemberMethods()) { > // no value, returns null > Object ourValue = memberValues.get(member); > ... > if (!memberValueEquals(ourValue, hisValue)) > ... > } > ... > } > > private static boolean memberValueEquals(Object v1, Object v2) { > Class<?> type = v1.getClass(); // NPE here > ... > } > > Like Rafael, I wonder if we can/should throw the > IncompleteAnnotationException when accessing the annotation member > implicitly with equals(), not with the named accessor. > > -Aleksey. > > On 11/16/2014 09:20 PM, joe darcy wrote: > > Hello, > > > > The reference type members of annotations are all required to be > non-null. > > > > Cheers, > > > > -Joe > > > > On 11/14/2014 1:51 AM, Rafael Winterhalter wrote: > >> For reasons I am not going into, I am implementing my own > >> AnnotationInvocationHandler and I want it to be compatible to the > >> OpenJDK's > >> annotation invocation handler with respect to the hash code and equals > >> functionality, thus I just looked at the source in more detail. During > >> implementing the handler, I realized that: > >> > >> 1. The invoke method applies a null check for an annotation value when > >> looking it up for explicitly reading an annotation property and throws > an > >> IncompleteAnnotationException if no value and no default value is > >> provided. > >> > >> 2. No such checks are applied when invoking the hashCode / equals / > >> toString methods for the annotation which all have their own handler > >> method. This would result in a NullPointerException for all of them. > >> > >> I did not find any formal specification for what is supposed to > >> happen. Is > >> it correct to throw these exceptions or should it rather also be an > >> IncompleteAnnotationException? > >> > >> Thanks for the info! Rafael > > > > >
