RFR JDK-8066709 Make some JDK system properties read only

[Roger Riggs]

Hi Stuart,

On 6/4/2018 9:52 PM, Stuart Marks wrote:
>
>
> On 6/4/18 6:32 AM, Roger Riggs wrote:
>> Please review a change to make the values of java.home, user.home, 
>> user.dir, and user.name
>> effectively read-only for internal use.  The values are cached during 
>> initialization and the
>> cached values are used.
>>
>> Webrev:
>> http://cr.openjdk.java.net/~rriggs/webrev-static-property-8066709/
>>
>> Issue:
>>    https://bugs.openjdk.java.net/browse/JDK-8066709
>>
>> CSR:
>>    https://bugs.openjdk.java.net/browse/JDK-8204235
>
> Hi Roger,
>
> Overall I think the intent of the change is a good one, as is the 
> reimplementation of internal uses of system properties to use an 
> internal API instead.
>
> I think it would be good to have an explicit initialization of the 
> SystemProperty class (or whatever it ends up being called) instead of 
> implicitly initializing via a static initializer. If the class is 
> initialized too early, for some reason, things would go wrong.
>
That would be a no-op;  I want the values of the properties to be final 
statics which means they have to
be initialized by the static initializer.
> Should there be an error, a warning, or assertion checking to make 
> sure that none of the cached values are null? They should all be 
> non-null, right?
Yes, null will be a fatal InternalError.

Thanks, Roger

>
> s'marks