How to start java nashorn with jjs arguments

Question

I would like to read a bytecode generated by nashorn engine. I have found that argument i need is -d=*folder* also i would like to apply optimistic types for better performace which are enabled by argument-ot

Im initializing the engine by calling methods:

ScriptEngine engine = new ScriptEngineManager().getEngineByName("nashorn");
engine.setBindings(bindings, ScriptContext.ENGINE_SCOPE);
engine.eval(myscriptfile);

But I have not found where am i supposed to put the jjs arguments.

Answer 1

The javax.script API doesn't let you pass these arguments. You'll need to use the explicit Nashorn API to get a script engine factory:

import jdk.nashorn.api.scripting.NashornScriptEngineFactory;

NashornScriptEngineFactory factory = new NashornScriptEngineFactory();
ScriptEngine engine = factory.getScriptEngine("--optimistic-types=true", "-d=someFolder");

Hope that helps.

Answer 2

Adding to what Attila said: you can set "nashorn.args" System property with the arguments you want to pass to Nashorn.

Pro: You can stick to javax.script API in your code and still pass arguments.

Con: This affects all the nashorn engines created in the process - whereas nashorn specific API allows you create different engine instances with different command line arguments. Also, you may not have control over System property setting in certain deployments.