Three questions about Java Scripting API.

[Dmitry Zhuravlev]

Guys,
here are three questions about java scripting api, please help.

(1) How can I get all the variables created inside my engine?
There are two kinds of variables: first kind is Java objects that I have put inside the engine, and second kind is the variables created inside my script, such as 'var a = 4;'. How can I list all the variables of that two kinds, or at least the second kind?

(2) Is there is a way to make 'import static' to the engine? I dont want to write MyClass.MyEnum.MyEnumItem inside my script every time. Also, I cannot put the whole enum into the engine with engine.put("MyEnum", MyEnum); I can put only enum items separately: engine.put("MyEnum", MyEnum.EnumItemA);. Thats why I ask about static import.

(3) How can I cast engine variables back to java variables inside my java code?
Here is my example:

package mypackage;
 
import java.util.ArrayList;
import java.util.List;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineFactory;
import javax.script.ScriptEngineManager;
 
public class Main
{
 
	public static void main(String[] args) throws Exception  
	{
 
		ScriptEngineManager mgr = new ScriptEngineManager();
		List<ScriptEngineFactory> factories = mgr.getEngineFactories();
		ScriptEngineManager factory = new ScriptEngineManager();
		ScriptEngine engine = factory.getEngineByName("JavaScript");
 
		ArrayList<Double> myList = new ArrayList<Double>();
		myList.add(5.0);				
		engine.put("MyList", myList);	
		engine.eval("MyVar = MyList.get(0);");
		System.out.println((Double)engine.get("MyVar"));
 
	}
}

The result is:

Exception in thread "main" java.lang.ClassCastException: sun.org.mozilla.javascript.internal.NativeJavaObject cannot be cast to java.lang.Double
at mypackage.Main.main(Main.java:28)

Is it possible to retrieve my Double java object from the engine?