title: check if an object is null
body: <p>I have a linked list in which first node contains null object. means firstNode.data is equal to null, firstNode.nextPointer = null, firstNode.previousPointer = null.</p>
  
  <p>And I want to check if firstNode is null or not.
  So I tried-</p>
  
  <pre><code>if(list.firstNode == null){
  
              //do stuff          
          }
  </code></pre>
  
  <p>but this doesn't works?</p>
  
  <p>I also tried equals too. Any suggestions?</p>
  
  <p>I tried printing. And I got as-</p>
  
  <p>{null} -- firstNode</p>