title: Why does a String causes a IllegalArgumentException by using a SimpleDateFormat?
body: <p>Why does this code causes an Illegal Argument Exception?    </p>
  
  <pre><code>final SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");
  dateFormat.format(new Date() + "23:59") // IllegalArgumentException occurs
  </code></pre>
  
  <p>The time was saved as a string. Is this the wrong way?</p>