title: Java what is the double underscore notation for?
body: <p>I was browsing the web and found <a href="http://www.java2s.com/Code/Java/Network-Protocol/UsetheFTPClient.htm" rel="noreferrer">this example</a>. Within the public static void main method is this line syntax which I have never seen before <code>__main:</code></p>
  
  <p>As in:</p>
  
  <pre><code>public class Klass {
      public static void main(String[] args) {
          // code goes here...
  __main:
          // and mode code here...
      }
  }
  </code></pre>
  
  <p>I tried punching this into eclipse and got a little yellow underline with a tool-tip which said "The label __main is never explicitly referenced".</p>
  
  <p>I can't find anything <a href="http://www.google.fr/search?q=+java%20label%20%22double%20underscore%22%20-jlabel" rel="noreferrer">online</a> and I'm really curious! I've been programming in Java for years and I've never seen this syntax before. What does it do, why would you use it, where can I learn more? </p>