title: Java - appending to Excel file with FileOutputStream
body: <p>This code appends to an already created Excel file:</p>
  
  <pre><code>FileOutputStream fileOut = new FileOutputStream("c:\\Decrypted.xls");
  </code></pre>
  
  <p>What can we add / modify so that Decrypted.xls should be created if not already created and appended if already created?</p>