Java 8 Nashorn Tutorial - from http://winterbe.com/posts/2014/04/05/java8-nashorn-tutorial/

NashornModule.java

import javax.script.Invocable;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.time.LocalDateTime;
import java.util.Date;
import java.util.Properties;

public class NashornModule {


    public final static void evalStatement() {
        System.out.println("NashornModule :: evalStatement \n");
        ScriptEngine engine = new ScriptEngineManager().getEngineByName("nashorn");
        try {
            engine.eval("print('Hello World!');");
        }
        catch(ScriptException exception) {
            System.err.println("Failed to evaluate exception");
        }
        System.out.println("\n");
    }

    public final static void evalScript() {
        System.out.println("NashornModule :: evalScript \n");
        ScriptEngine engine = new ScriptEngineManager().getEngineByName("nashorn");
        try {
            engine.eval(new FileReader("script.js"));
        }
        catch (FileNotFoundException exception) {
            System.err.println("Failed to find script.js");
            System.exit(0);
        }
        catch(ScriptException exception) {
            System.err.println("Failed to evaluate FileReader(script.js)");
            System.exit(0);
        }

        Invocable invocable = (Invocable) engine;
        try {
            Object result = invocable.invokeFunction("fun1", "Peter Parker");
            System.out.println(result);
            System.out.println(result.getClass());
        }
        catch(NoSuchMethodException exception) {
            System.err.println("No such method fun1");
        }
        catch(ScriptException exception) {
            System.err.println(exception);
        }
        System.out.println("");

        try {
            invocable.invokeFunction("fun2", new Date());
            invocable.invokeFunction("fun2", LocalDateTime.now());
            invocable.invokeFunction("fun2", new Properties());
        }
        catch(NoSuchMethodException exception) {
            System.err.println("No such method fun2");
        }
        catch(ScriptException exception) {
            System.err.println(exception);
        }

        System.out.println("\n");
    }

    public static String fun1(String name) {
        System.out.format("Hi there from Java: %s", name);
        return "greetings from java";
    }

    public static void fun2(Object object) {
        System.out.println(object.getClass());
    }

    public static void main(String[] args) {
        evalStatement();
        evalScript();
    }
}

script.js

// Invoking Javascript Functions from Java
var fun1 = function(name) {
    print('Hi there from Javascript, ' + name);
    return "greetings from javascript";
};

var fun2 = function (object) {
    print("JS Class Definition: " + Object.prototype.toString.call(object));
};