ClassCastException on collection generics for jdk8 working code

[Remi Forax]

I think this is due to the fix of 8043741 [1].
In my opinion, these legacy tests are buggy and because of a bug in the 
compiler
it was working, and not the other way around.

Anyway, it's just my opinion, there is a lot of corner cases around the 
cast to an interface,
asking the experts is a better idea so I've CC compiler-dev.

Rémi

[1] https://bugs.openjdk.java.net/browse/JDK-8043741

On 01/17/2015 07:51 PM, Emanuel wrote:
> Thank you Martijn, i didn't know :)
>
> here we go :
> https://gist.github.com/tglman/02eb98fb1c80386fa3ab
> https://gist.github.com/tglman/44b0b3fc4239d9229027
>
> Let me add also that OrientDB don't rely in any way on this behavior, it
> come out just from two not well written legacy test case ;).
>
> On 01/17/2015 05:11 PM, Martijn Verburg wrote:
>> Hi Emanuel,
>>
>> Good to see you today! OpenJDK mailing lists strip attachments so
>> you'll need to give a pastebin link or similar.
>>
>> Cheers,
>> Martijn
>>
>> On 17 January 2015 at 16:58, Emanuel <emanuele.tagliaferri at gmail.com
>> <mailto:emanuele.tagliaferri at gmail.com>> wrote:
>>
>>      I am at the Adopt OpenJdk hack day organized by the LJC, I am running
>>      tests cases of OrientDB (open source java based NoSql) on JDK9 (Build
>>      b45 ), and i got some issue with the use of generics.
>>
>>      basically this code:
>>              List<Date> list = new ArrayList<>();
>>              list.add(new Date());
>>
>>              List<Foo> cList = (List<Foo>) (List<?>) list;
>>              Date date = (Date) cList.get(0);                        // it
>>      fail here
>>
>>      on jdk8 it work fine, on jdk9 the code fail in the marked line.
>>
>>      the jdk8 bytecode for the failing line is:
>>            invokeinterface #7,  2            // InterfaceMethod
>>      java/util/List.get:(I)Ljava/lang/Object;
>>            checkcast     #4                  // class java/util/Date
>>
>>      instead of  on jdk9 is:
>>            invokeinterface #7,  2            // InterfaceMethod
>>      java/util/List.get:(I)Ljava/lang/Object;
>>            checkcast     #8                  // class ListFail$Foo
>>            checkcast     #4                  // class java/util/Date
>>
>>
>>      and is clear that there's a additional cast that is causing the
>>      exception.
>>
>>      I understand that this code is not the exactly clean and correct
>>      conceptually, but it may be a lot of this staff out there that can be
>>      break by jdk9.
>>
>>      In attachment a couple of simple example for reproduce this issue.
>>
>>
>>      Regards
>>
>>      Emanuel
>>
>>
>>