title: Unable to create connection in Oracle SQL developer . IO error
body: <p>I cannot add a connection in oracle SQL developer installed.<br>
  The error I am getting is:</p>
  
  <blockquote>
    <p>IO Error :The network adapter could not establish connection. </p>
  </blockquote>
  
  <p>Also can anyone help me as to what user name and password it is asking?<br>
  Is there anything else I need to install.</p>