title: The Network Adapter could not establish the connection in SQL developer
body: <p>I created a database using SQL developer list of 1000 entries and it created successfully. The connection also succeeded. But today while I'm trying to connect there is an error occurring: </p>
  
  <pre><code>IO Error: The Network Adapter could not establish the connection in SQL developer
  </code></pre>
  
  <p>I can surely say it is not connecting I tried it in <code>Command prompt</code> also in prompt it is mentioning as Protocol Adapter Error.</p>
  
  <p>What is the problem here?</p>
  
  <p>What is meant by Protocol Adapter Error how can i overcome it?</p>
  
  <p>What is Network Adapter Error?</p>