The class cache

Tal Liron tal.liron at
Wed Mar 12 11:44:30 UTC 2014

Hannes, I would like to test this.

It doesn't seem to be on the main Nashorn repository:

Is there a separate repository I should be using?

On 03/12/2014 05:50 PM, Hannes Wallnoefer wrote:
> Hi Tal,
> I'm right now pushing a change for JDK-8021350 that allows sharing 
> script classes between global scopes. Currently, script classes are 
> bound to the global object in various ways, so the change is not 
> trivial, and it's not possible to share compiled scripts between 
> global scopes with the nashorn.jar in current JDK8 builds. The script 
> sharing feature is planned for the 8u20 release.
> The class sharing will be per script engine, meaning that if you use 
> multiple scopes with one script engine classes will be reused, when 
> you use multiple script engines scripts will be recompiled for each 
> engine.
> I'd be interested to know whether this would work for you. If you'd 
> like to test the class sharing feature I can help you getting started.
> Hannes
> Am 2014-03-12 10:27, schrieb Tal Liron:
>> In Nashorn, the ClassCache is set per Global instance.
>> This is fine if your application has only one global instance. 
>> However, my application design involves creating many Global 
>> instances. (Actually, I create and destroy them on the fly per user 
>> request in an HTTP server scenario.) The problem is that all code has 
>> to constantly be recompiled, and the cache is essentially never used. 
>> Since recompilation is so very expensive in Nashorn, this results in 
>> awful performance.
>> How can I implement a shared ClassCache? I can't extend and modify 
>> Global behavior, because it's a final class.
>> I've tried to cache ScriptFunction instances myself, but I get 
>> exceptions when I try to run them with a different Global instance 
>> than the one that created them.

More information about the nashorn-dev mailing list