Java ScriptEngine access variable in Javascript

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

public class Main {
  public static void main(String[] args) {
    // Get the Nashorn engine
    ScriptEngineManager manager = new ScriptEngineManager();
    ScriptEngine engine = manager.getEngineByName("JavaScript");

    // Write a script that declares a global variable named year and
    // assign it a value of 1969.
    String script = "var year = 2020";

    try {//  ww w.  ja  v  a  2 s. co m
      // Execute the script
      engine.eval(script);

      // Get the year global variable from the engine
      Object year = engine.get("year");

      // Print the class name and the value of the variable year
      System.out.println("year's class: " + year.getClass().getName());
      System.out.println("year's value: " + year);
    } catch (ScriptException e) {
      e.printStackTrace();
    }
  }
}