title: Unable to open Pyspark Shell
body: <p>I am running <code>./bin/pyspark</code> at to open the pyspark shell but I get the following error :</p>
  
  <pre><code>`py4j.protocol.PY4JNetworkError: An error occurred while trying to connect to the Java Server`
  </code></pre>
  
  <p>Searched about it a lot. Couldn't find a solution. 
  How should I resolve this ?</p>
  
  <p>Thanks,</p>