Javaで実行したJavaScriptからJavaメソッドをコールする

■本家のドキュメント(1)
https://docs.oracle.com/javase/jp/6/technotes/guides/scripting/programmer_guide/
■本家のドキュメント(2)
https://developer.mozilla.org/ja/docs/Rhino/Scripting_Java

package pkg;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;
public class HelloJavaScript {
	public void run() {
		System.err.println("hello!");
	}
	public static void main(String[] args) {
		// see
		// https://developer.mozilla.org/ja/docs/Rhino/Scripting_Java
		// These packages are likely not in the java package, so you'll need to
		// prefix the package name with "Packages."

		// Get the JavaScript engine
		ScriptEngineManager manager = new ScriptEngineManager();
		ScriptEngine engine = manager.getEngineByName("JavaScript");
		String script = "" //
				+ "var obj = new Packages.pkg.HelloJavaScript();" //
				+ "obj.run();" //
		;
		try {
			engine.eval(script);
		} catch (ScriptException e) {
			e.printStackTrace();
		}
	}
}