title: How to do calendar operations in Java GWT? How to add days to a Date?
body: <p>Since GWT does not provide the GregorianCalendar class, how to do calendar operations on the client?</p>
  
  <p>I have a Date <code>a</code> and I want the Date, which is <code>n</code> days after <code>a</code>.</p>
  
  <p>Examples:</p>
  
  <pre><code>a (2000-01-01) + n (1) -&gt; 2000-01-02
  a (2000-01-01) + n (31) -&gt; 2000-02-01
  </code></pre>