RFR(L) 8136930: Simplify use of module-system options by custom launchers

[Coleen Phillimore]

On 7/21/16 3:25 AM, Alan Bateman wrote:
> On 20/07/2016 22:47, Coleen Phillimore wrote:
>
>>
>>
>> Why aren't addmods and limitmods allowed be specified more than once 
>> on the command line and handled like the other ones?
> It's last one wins, typical for most options when repeated. I could 
> imagine someone composing a command line with --add-modules coming 
> from multiple sources, they logically merge/union, so maybe there is a 
> case for that. However --limit-modules is niche and I don't think 
> makes sense to attempt to merge.

Well having subtle differences like this makes it difficult to explain 
to people, and nobody reads documentation in that much detail.  It seems 
like you should try to be consistent, if it makes sense.  But no, I 
don't know what limitmods does or whether you'd want to aggregate this.

Coleen
>
>>
>> We should add an option -XX:+UseUnsafe to be a shortcut for this:
>>
>> --add-exports=java.base/jdk.internal.misc=ALL-UNNAMED
> That may be useful for JDK tests but it makes it too easy to get to 
> jdk.internal.misc.Unsafe. For usages outside of the JDK then I think 
> they should continue to use sun.misc.Unsafe (JEP 260 etc.) and 
> gradually reduce that over time as better approaches are available in 
> the platform.
>
> -Alan