title: Java: Protect Trial/Demo Period
body: <p>I searched, and only found a couple([<a href="https://stackoverflow.com/questions/2146315">1</a>][<a href="https://stackoverflow.com/questions/2769384">2</a>]) of answers here.  None of them really answer my question though.</p>
  
  <p>My application will have a thirty day trial period.  What's the best way to protect the program?  I'm not worried about crackers, just Joe Average reinstalling the program.  Setting back the clock isn't really a concern either.</p>