title: Setting connection reference to null after closing it
body: <p>Is it required/good practice to set the connection reference to null after closing it?</p>
  
  <p>I am closing connections in <code>finally</code> block.</p>
  
  <pre><code>conn.close();
  conn = null;
  </code></pre>
  
  <p>I am facing connection wait timeout exception during performance testing 
  as the maximum connections are getting exceeded.</p>