Here's my full code:

import javax.script.*;

public class TestF {
    public static void main(String[] args) throws Exception {
        // create a script engine manager
        ScriptEngineManager factory = new ScriptEngineManager();
        // create a Nashorn script engine
        ScriptEngine engine = factory.getEngineByName("nashorn");
        // evaluate JavaScript statement
        try {
            engine.eval("print('Hello, World!');");
        } catch (final ScriptException se) {
            se.printStackTrace();
        }
    }
}

I'm using Arch and just downloaded Java and have the Java extension on VSCode. I can run any other programs in Java but have not installed any external modules/packages. Running the above program gives me

Exception in thread "main" java.lang.NullPointerException: Cannot invoke "javax.script.ScriptEngine.eval(String)" because "<local2>" is null

It seems like factory.getEngineByName("nashorn") is returning null. Do I need to externally download Nashorn? Because this says it's already included automatically. Or is nashorn not supported anymore? Because this says I can still use it. I'm using the latest version of Java18 from their official website.