Nashorn Standalone 15.3 engine returned is null

[Attila Szegedi]

Can you check if this is specific to 15.3, or does it also not work with e.g. 15.2?

Attila.

> On 2021. Jul 15., at 12:49, Andreas Mueller <am at iit.de> wrote:
> 
> Tested it again with listing the engine right befor getByName:
> 
> List<ScriptEngineFactory> factories = manager.getEngineFactories();
> for (int i = 0; i < factories.size(); i++) {
>     ctx.logSwiftlet.logInformation(ctx.streamsSwiftlet.getName(), "name=" + factories.get(i).getEngineName() +
>             ", version=" + factories.get(i).getEngineVersion() + ", language name=" + factories.get(i).getLanguageName() +
>             ", language version=" + factories.get(i).getLanguageVersion() +
>             ", names=" + factories.get(i).getNames());
> }
> engine = manager.getEngineByName((String) entity.getProperty("script-language").getValue());
> 
> It is listed but returns null. This code is executed by a dedicated class loader.
> 
> -- 
> Andreas Mueller
> IIT Software GmbH
> http://www.swiftmq.com <http://www.swiftmq.com/>
> 
> <swiftmq_logo_positiv.png>
> 
>> On 15. Jul 2021, at 10:59, Andreas Mueller <am at iit.de <mailto:am at iit.de>> wrote:
>> 
>> Hi Attila,
>> 
>> thanks but didn’t work in my environment. 
>> 
>> Tried every combination (using “nashorn”, “JavaScript” as name, using class path, using module path). 
>> 
>> Fact is, it lists the Nashorn engine correctly:
>> 
>> ScriptEngineManager manager = new ScriptEngineManager();
>> List<ScriptEngineFactory> factories = manager.getEngineFactories();
>> for (int i = 0; i < factories.size(); i++) {
>>     ctx.logSwiftlet.logInformation(ctx.streamsSwiftlet.getName(), "name=" + factories.get(i).getEngineName() +
>>             ", version=" + factories.get(i).getEngineVersion() + ", language name=" + factories.get(i).getLanguageName() +
>>             ", language version=" + factories.get(i).getLanguageVersion() +
>>             ", names=" + factories.get(i).getNames());
>> }
>> 
>> 2021-07-15 10:51:37.948/sys$streams/INFORMATION/name=OpenJDK Nashorn, version=15.3, language name=ECMAScript, language version=ECMA - 262 Edition 5.1, names=[nashorn, Nashorn, js, JS, JavaScript, javascript, ECMAScript, ecmascript]
>> 
>> But return null here:
>> 
>> engine = manager.getEngineByName(“JavaScript”);
>> 
>> I suspect it might have to do with class loaders as we use a dedicated class loader for every script:
>> 
>> ScriptEngineManager manager = new ScriptEngineManager();
>> ClassLoader classLoader = createClassLoader();
>> streamContext.classLoader = classLoader;
>> Thread.currentThread().setContextClassLoader(classLoader);
>> 
>> Thanks,
>> Andreas
>> 
>> -- 
>> Andreas Mueller
>> IIT Software GmbH
>> http://www.swiftmq.com <http://www.swiftmq.com/>
>> 
>> <swiftmq_logo_positiv.png>
>> 
>>> On 13. Jul 2021, at 16:01, Attila Szegedi <szegedia at gmail.com> wrote:
>>> 
>>> I’m honestly not sure. I have this very small test program:
>>> 
>>> import javax.script.*;
>>> 
>>> public class X {
>>>    public static void main(String[] args) throws ScriptException {
>>> 	ScriptEngineManager factory = new ScriptEngineManager(); 
>>> 	ScriptEngine engine = factory.getEngineByName("JavaScript"); 
>>> 	engine.eval("function f() { print('Hello, World!'); } f()");
>>>    }
>>> }
>>> 
>>> if I put it in a directory where I checked out Nashorn repo, and run “ant jar” to build the JAR file and run:
>>> 
>>> java --module-path build/nashorn/dist:build/nashorn/dependencies X.java
>>> 
>>> It prints "Hello, World!” as expected, so it definitely find the engine under the name “JavaScript". I can also run it with classpath instead of module path:
>>> 
>>> java -cp build/nashorn/dist/nashorn.jar:build/nashorn/dependencies/asm-7.3.1.jar:build/nashorn/dependencies/asm-util-7.3.1.jar X.java
>>> 
>>> and that works too. Do you have the dependencies (ASM) too?
>>> 
>>> Attila.
>>> 
>>>> On 2021. Jul 13., at 15:33, Andreas Mueller <am at iit.de> wrote:
>>>> 
>>>> Hi,
>>>> 
>>>> I’ve added Nashorn to Java 15 and it is properly displayed when listing the engines:
>>>> 
>>>> 2021-07-13 15:14:30.233/sys$streams/INFORMATION/starting, available Scripting Engines:
>>>> 2021-07-13 15:14:30.246/sys$streams/INFORMATION/name=OpenJDK Nashorn, version=15.3, language name=ECMAScript, language version=ECMA - 262 Edition 5.1, names=[nashorn, Nashorn, js, JS, JavaScript, javascript, ECMAScript, ecmascript]
>>>> 
>>>> However, when I get the engine with name “JavaScript” it returns null:
>>>> 
>>>> engine = manager.getEngineByName((String) entity.getProperty("script-language").getValue());
>>>> if (engine == null)
>>>>    throw new Exception("Engine for script-language '" + entity.getProperty("script-language").getValue() + "' not found!");
>>>> 
>>>> 2021-07-13 15:14:30.361/ERROR/Exception occured: java.lang.Exception: Engine for script-language 'JavaScript' not found!
>>>> 
>>>> Any ideas what the problem could be?
>>>> 
>>>> Thanks,
>>>> Andreas
>>>> -- 
>>>> Andreas Mueller
>>>> IIT Software GmbH
>>>> http://www.swiftmq.com <http://www.swiftmq.com> 
>>>> 
>>>> 
>>> 
>> 
>