Cappuccino - The Node.js Project(cappuccino-project.org)

    Button b = new Button("Click me", new ClickHandler() {
      public void onClick(ClickEvent event) {
        //do something
      }
    });

    Button b = new Button("Click Me");
    b.addActionListener(new ActionListener(){
        void actionPerformed(ActionEvent e){
            //do something
        }
    });