title: How to Force IPv4 on apache httpclient? (java)
body: <p>My program always get stuck for 30 seconds on </p>
  
  <pre><code>[DEBUG] SingleClientConnManager - Get connection for route HttpRoute[{}-&gt;http://foobar.com]
  </code></pre>
  
  <p>Further investigation suggests this is due to ipv4 fallback. 
  Is there anyway to force ipv4 on httpclient to resolve the issue?</p>
  
  <p>P.S.
  I believe it is a IPv4 problem because <code>curl -L04 http://foobar.com</code> is an instantanious download, while <code>curl -L06 http://foobar.com</code> produces <code>curl: (6) Couldn't resolve host 'foobar.com'</code></p>