title: What is it called, when you add a new actionlistener with a method while already in a method?
body: <p>Just to make sure, this is what I mean:</p>
  
  <pre><code>public static void someMethod()
  {
      JButton btn = new JButton();
      btn.addActionListener(new ActionListener()
      {
          public void actionPerformed(ActionEvent e)
          {
              // Do something...
          }
      });
  }
  </code></pre>
  
  <p>So when adding an ActionListener to the button, I create a new ActionListener and a new method inside a method - but what is this implementation of an ActionListener called?</p>