Recently, Stephen Colebourne and Stefan Schulz post another closure like proposal, yes, yet another one.

They propose another syntax for describing a closure which, in my opinion, is more a simpler way to declare an inner-class.
I am not a big fan of this proposal, i definitively prefer the closure syntax decribed by Neal Gafter.
But there is something that i like in their proposal, the fact that you can create invocable method references.

Invocable Method Reference

We need a way to easily create a reference to a method, an object that allow to call a method. Currently a method is not an Object and if you want something like that you have to use reflection (java.lang.reflect.Method) which is not type-safe, uses lot of checked exceptions and performs primitive boxing and array boxing.

So having a way to create a method reference is a good think. But unlike Stephen and Stefan, i don't think that a method reference is a java.lang.reflect.Method correctly typed by the compiler but instead a java.function object (a closure) of Neal.
In my opinion method reference is a kind of closure litteral, so this code snippet:

  public void init() {
    JButton button = ...;
    button.addActionListener(this#handleAction(ActionEvent));
  }
  public void handleAction(ActionEvent ev) {
    // handle event
  }

is a short syntax for:

  public void init() {
    JButton button = ...;
    button.addActionListener({ActionEvent e=>
      handleAction(e);
    });
  }
  public void handleAction(ActionEvent ev) {
    // handle event
  }

Because a method reference is a closure litteral, the type of a method reference is a function type.

 {ActionEvent=>void} handle = this#handleAction(ActionEvent);

I think that using # is a good idea. Perhaps because it's the syntax i choose to use to create property litteral (property reference) in my next property proposal that i will post in few days.

Cheers, Rémi