title: Talend Display null as empty array
body: <p>I new at talend stuck with a basic issue ,any help would be really appreicated
  I have a talend esb job that let me query my database via get request </p>
  
  <p>Job Flow:
  <img src="https://i.stack.imgur.com/g3Ora.jpg" alt="Job Flow"></p>
  
  <p>Job flow is like:-</p>
  
  <pre><code>Trestrequest==&gt;tflowIterate==&gt;Redshift==&gt;txmlmap==&gt;trestresponse
  </code></pre>
  
  <p>Call:</p>
  
  <pre><code>localhost/restaurant?rest_id=305&amp;from_date=%272016-10-12%27&amp;to_date=%272016-10-18%27&amp;_=1476875037045
  </code></pre>
  
  <p>get the result(Json response)</p>
  
  <pre><code>{"root":{"combo3":[{"class1":11963,"class2":12405,"class3":13050,"count":12}
  </code></pre>
  
  <p>which is perfect and what is required</p>
  
  <p>How can I handle <code>404 exception</code> for Talend ESB and display 
  <code>{}</code> (in web page or web browser)</p>
  
  <p>Right now I only see empty webpage as result but how can I replace it with 
  <code>{}</code> (in web page or web browser)</p>