title: URI - getHost returns null. Why?
body: <p>Why is the 1st one returning <code>null</code>, while the 2nd one is returning <code>mail.yahoo.com</code>?</p>
  
  <p>Isn't this weird? If not, what's the logic behind this behavior?  </p>
  
  <p>Is the underscore the culprit? Why? </p>
  
  <pre><code>public static void main(String[] args) throws Exception {
      java.net.URI uri = new java.net.URI("http://broken_arrow.huntingtonhelps.com");
      String host = uri.getHost();
      System.out.println("Host = [" + host + "].");
  
      uri = new java.net.URI("http://mail.yahoo.com");
      host = uri.getHost();
      System.out.println("Host = [" + host + "].");
  }
  </code></pre>