RFR (trivial) 8189794: Assert in InstanceKlass::cast called from Exceptions::new_exceptions

[serguei.spitsyn at oracle.com]

Hi Coleen,

Looks good.

Thanks,
Serguei


On 10/23/17 15:29, coleen.phillimore at oracle.com wrote:
> Summary: Fix call to InstanceKlass::cast to only be after verifying 
> class is non-null.
>
> Also fixed an unnecessary InstanceKlass::cast found while looking for 
> similar instances of this bug.  I didn't find this same bug anywhere 
> else.  Tested with internal vm.gc.locker tests, and with JPRT which is 
> equivalent to tier1 only faster at the moment.
>
> open webrev at http://cr.openjdk.java.net/~coleenp/8189794.01/webrev
> bug link https://bugs.openjdk.java.net/browse/JDK-8189794
>
> Thanks,
> Coleen