Manifest Add-Exports vs. command line --add-exports

Peter Levart peter.levart at
Thu Aug 24 08:10:26 UTC 2017


On 08/23/2017 11:24 PM, Tom Hood wrote:
>> The CLI options to export or open packages can be specified in JNLP file,
>> you shouldn't need to ask user to add them via the control panel. You can
>> predicate on the Java SE version too, i.e.
>>    <j2se version="9+" java-vm-args="--add-opens=..." />
> The issue is the limit on the *number* of args we can have in the
> java-vm-args.  If you exceed the limit, the webstart app fails to launch
> and displays a popup window with the text "too many args to run".
> We need so many --add-exports and --add-opens that it's possible we won't
> be able to fit them all in there.  At the moment, we are just under the
> limit and I'm hoping further testing of our app doesn't push us over the
> edge by revealing more --add-opens, for example.
> I can't shrink the list of args by using --illegal-access=permit, because
> that is disallowed in the jnlp.  I think I saw some correspondence from you
> indicating you intentionally wanted the jnlp to explicitly list what was
> needed.  Unfortunately, that won't work if you have too many to list.
> Any chance you could change Java 9 to allow --illegal-access=permit in the
> jnlp or alternatively increase the number of args allowed?

I think that this problem could be solved by WebStart composing the JVM 
arguments into a temporary file and using the new JDK 9 @<filepath> 
syntax to launch the app.

Any chance that WebStart gets open-sourced?

Regards, Peter

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