title: Check if two date periods overlap
body: <ul>
  <li>I have two date ranges, (start1,end1):::>>date1  &amp;&amp; (start2,end2):::>>date2  .</li>
  <li><p>I want to check if the two dates isOverLaped.</p></li>
  <li><p>My flow chart <strong>I assume "&lt;>=" operators is valid for comparing</strong>.</p>
  
  <pre><code>boolean isOverLaped(Date start1,Date end1,Date start2,Date end2) {
      if (start1&gt;=end2 &amp;&amp; end2&gt;=start2 &amp;&amp; start2&gt;=end2) {
          return false;
      } else {
          return true;
      }
  }
  </code></pre></li>
  <li>Any Suggestion will be appreciated. </li>
  </ul>