How to extend a Java interface or class with overloaded methods using Nashorn?

[A. Sundararajan]

Hi Christopher,

http://mail.openjdk.java.net/pipermail/nashorn-dev/2015-February/004178.html

Somehow missed responding to this email. Yes, you can implement 
interface with overloaded methods. You can use arguments inside the 
implementing function to differentiate.

var Foo = Java.type('bar.Foo');
var instance = new Foo {
   bar: function(){
      print(arguments.length);
      for (i in arguments) print(arguments[i]);
   }
  };

instance.bar();
instance.bar(223);
instance.bar("hello");

Hope this helps,
-Sundar