Running Nashorn under java.lang.instrument

[David P. Caldwell]

Part of the issue is that I was incorrect that Nashorn would be loaded
by the system class loader; it is actually loaded by the extensions
class loader, so my code will indeed attempt to instrument Nashorn
itself. I don't know whether that should work or not, but it's not
what I was trying to do, so I'm going to continue debugging and will
report back if and as I find useful things.

On Mon, Oct 13, 2014 at 5:37 PM, David P. Caldwell
<david at code.davidpcaldwell.com> wrote:
> So if I run Nashorn under a Java agent, I can't start it. I haven't
> yet dug into the error, but when I invoke:
>
> return new ScriptEngineManager().getEngineByName("nashorn") != null
>
> , which is my "is Nashorn installed" check, the following prints to System.err:
>
> ScriptEngineManager providers.next():
> javax.script.ScriptEngineFactory: Provider
> jdk.nashorn.api.scripting.NashornScriptEngineFactory could not be
> instantiated
>
> Does anyone immediately know what would be wrong?
>
> My Transformer in the class does this:
>
> if (protectionDomain == null) return null;
>
> ... so it shouldn't be attempting to transform any Nashorn classes.
>
> On the other hand, if it's relevant, the ClassLoader that loaded the
> class above that executes return new ScriptEngineManager() ... is not
> loaded by the system class loader; it's loaded by an URLClassLoader
> that sits on top of that (it does delegate to the system class
> loader). Under normal circumstances, this wouldn't make a difference,
> but just in case ...
>
> Anyone immediately have an idea what I might be dealing with here?
>
> -- David P. Caldwell
> http://www.davidpcaldwell.com/