How can we Get Script engine by extension name

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

public class GetEngineByExtensionDemo {
public static void main(String[] args) {
ScriptEngineManager manager = new ScriptEngineManager();
/* Retrieve a ScriptEngine that supports scripts with .js extension */
ScriptEngine jsEngine = manager.getEngineByExtension("js");
System.out.println(jsEngine);
}
}