title: How to replace from null value empty string in java?
body: <p>I'm getting the <code>null</code> values from DB, but I need to display the empty string <code>""</code> instead.</p>
  
  <p><br>
  For example, I have to append four values to display in the single cell of a Excel sheet like below:</p>
  
  <pre><code>sheet.addCell(new Label(4, currentRow, a.getPar()+" "+a.getO()+" "+a.getPar()));
  </code></pre>
  
  <p><br>
  How to achieve the expected result (the replacement) in Java?</p>