Nashorn Standalone 15.3 engine returned is null

[Andreas Mueller]

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> 



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>