import java.io.FileReader;

import javax.script.ScriptEngine;

import javax.script.ScriptEngineManager;

public class RunScriptFileDemo {

  public static void main(String[] args) {

    ScriptEngineManager manager = new ScriptEngineManager();

    ScriptEngine engine = manager.getEngineByName("js");

    try {

      FileReader reader = new FileReader("yourFile.js");

      engine.eval(reader);

      reader.close();

    } catch (Exception e) {

      e.printStackTrace();

    }

  }

}

/* File: yourFile.js

 * 

 function add(a, b) {

    c = a + b;

    return c;

}

result = add (10, 5);

print ('Result = ' + result);

*/