Java ScriptEngine run Javascript file

import java.io.IOException;
import java.io.Reader;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

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

public class Main {
  public static void main(String[] args) {
    ScriptEngineManager manager = new ScriptEngineManager();
    ScriptEngine engine = manager.getEngineByName("JavaScript");
    if (engine == null) {
      System.out.println("JavaScript engine is not available. ");

      return;// www. j av a  2s.  c  o m
    }
    try {
      Path scriptPath = Paths.get("JavaScript.txt").toAbsolutePath();
      if (!Files.exists(scriptPath)) {
        System.out.println(scriptPath + " script file does not exist.");
        return;
      }

      try (Reader reader = Files.newBufferedReader(scriptPath);) {
        Object result = engine.eval(reader);
        System.out.println("Result of " + scriptPath + " = " + result);
      }
    } catch (ScriptException | IOException e) {
      e.printStackTrace();
    }

  }
}