RFR 8147772: Some KerberosTicket methods throw NPE after being destroyed

[Sean Mullan]

On 01/19/2016 10:32 PM, Wang Weijun wrote:
> http://cr.openjdk.java.net/~weijun/8147772/webrev.00/
>
> No spec change, just safer return value.

I think it would be useful to update the specification to indicate how 
these methods behave when the object has been destroyed. I also noticed 
that many of the methods do not declare that they throw 
IllegalStateException when destroyed, so I think a general cleanup of 
the specification would be a good thing to do as part of this issue for 
JDK 9.

Thanks,
Sean