title: Why do Java webapps use .do extension? Where did it come from?
body: <p>I have always wondered why so many Java developers use ".do" as the extension for their web controller (MVC) resources. Example: <a href="http://example.com/register.do">http://example.com/register.do</a></p>
  
  <p>It doesn't even seem to be framework specific as I have seen it in Spring MVC and Struts projects.
  Where did this ".do" extension practice come from. Why was this done instead of no extension?
  I feel like I missed the Java world memo on this.</p>
  
  <p>Personally I prefer no extension.</p>