import static java.lang.System.out;

import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;

import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;

public class TryOutJavaScript {

   public static void main(String[] args) {
      new TryOutJavaScript().runInlineJSCode();
      new TryOutJavaScript().runExternalJSCode();
   }

   void runInlineJSCode() {
      ScriptEngineManager scriptMgr = new ScriptEngineManager();
      ScriptEngine jsEngine = scriptMgr.getEngineByName("JavaScript");
      try {
        jsEngine.eval("print('Hello from inline exec!')");
        out.println();
      } 
      catch (ScriptException ex) {
        ex.printStackTrace();
      }
   }

   void runExternalJSCode() {
      ScriptEngineManager scriptMgr = new ScriptEngineManager();
      ScriptEngine jsEngine = scriptMgr.getEngineByName("JavaScript");
      InputStream is = this.getClass().getResourceAsStream("greetings.js");
      try {
        Reader reader = new InputStreamReader(is);
        jsEngine.put("name", "Mathew");
        out.println(jsEngine.eval(reader));
        out.println(jsEngine.get("name"));
      } 
      catch (ScriptException ex) {
        ex.printStackTrace();
      }
   }
}

function Greeter()
{
}

Greeter.prototype.saySomething = function() {
   name = name + "! ";
   return "JavaScript says - how do u do " + name;
}

var grt = new Greeter();
grt.saySomething();

Hello from inline exec!
JavaScript says - how do u do Mathew! 
Mathew!